Prolactin

Distribution by Scientific Domains
Distribution within Medical Sciences

Kinds of Prolactin

  • serum prolactin

  • Terms modified by Prolactin

  • prolactin concentration
  • prolactin level
  • prolactin receptor
  • prolactin release
  • prolactin response
  • prolactin secretion

  • Selected Abstracts


    Effects of prolactin on intracellular calcium concentration and cell proliferation in human glioma cells

    GLIA, Issue 3 2002
    Thomas Ducret
    Abstract Prolactin (PRL) has several physiological effects on peripheral tissues and the brain. This hormone acts via its membrane receptor (PRL-R) to induce cell differentiation or proliferation. Using reverse transcription,polymerase chain reaction (RT-PCR) combined with Southern blot analysis, we detected PRL-R transcripts in a human glioma cell line (U87-MG) and in primary cultured human glioblastoma cells. These transcripts were deleted or not in their extracellular domains. We examined the effects of PRL on intracellular free Ca2+ concentration ([Ca2+]i) in these cells in order to improve our understanding of the PRL transduction mechanism, which is still poorly documented. [Ca2+]i was measured by microspectrofluorimetry using indo-1 as the Ca2+ fluorescent probe. Spatiotemporal aspects of PRL-induced Ca2+ signals were investigated using high-speed fluo-3 confocal imaging. We found that physiological concentrations (0.4,4 nM) of PRL-stimulated Ca2+ entry and intracellular Ca2+ mobilization via a tyrosine kinase,dependent mechanism. The two types of Ca2+ responses observed were distinguishable by their kinetics: one showing a slow (type I) and the other a fast (type II) increase in [Ca2+]i. The amplitude of PRL-induced Ca2+ increases may be sufficient to provoke several physiological responses, such as stimulating proliferation. Furthermore, PRL induced a dose-dependent increase in [3H]thymidine incorporation levels and in cellular growth and survival, detected by the MTT method. These data indicate that PRL induced mitogenesis of human glioma cells. GLIA 38:200,214, 2002. © 2002 Wiley-Liss, Inc. [source]


    Prolactin and macroprolactin in patients with systemic lupus erythematosus

    INTERNATIONAL JOURNAL OF RHEUMATIC DISEASES, Issue 3 2008
    Mohammadhassan JOKAR
    Abstract Aim: The aim of this study was to evaluate plasma levels of prolactin and macroprolactin in a group of systemic lupus erythematosus (SLE) patients and to determine if prolactin and macroprolactin concentrations were related to disease activity, clinical features or serological abnormalities. Methods: Ninety consecutive Iranian patients with SLE were tested for serum prolactin and macroprolactin levels. Total prolactin was measured directly in serum samples by radioimmunoassay. Free prolactin was extracted from the serum using polyethylene glycol. Clinical manifestation and SLE disease activity index (SLEDAI) were recorded. Auto antibodies were determined by standard techniques. Results: There were 90 patients (7 male, 83 female) with a mean age of 27.6 ± 9.1 (range 14,52). The mean disease duration was 27.6 ± 9.1 months. The frequency of high prolactin and macroprolactin, respectively, was 10% (9/90) and 5.6% (5/90) in patients with SLE. Macroprolactinemia was found in 55.55% (5/9) of hyperprolactinemic patients. Lupus activity was present in 63.3% (57/90) of patients without a significant difference in the frequency of high serum prolactin and macroprolactin levels when compared to inactive lupus. There were no statistically significant differences regarding demographic, clinical and laboratory characteristics between the group of patients with macroprolactinemia and the group without macroprolactinemia. Conclusion: Our results suggest that a subgroup of SLE patients have hyperprolactinemia and macroprolactinemia but they do not seem to have positive or negative correlation to clinical and laboratory features and disease activity. [source]


    Extracellular matrix regulates alpha s1-casein gene expression in rabbit primary mammary cells and CCAAT enhancer binding protein (C/EBP) binding activity

    JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2001
    Geneviève Jolivet
    Abstract Previous studies have shown that both the signal transducer and activator of transcription 5 (STAT5) and the CCAAT enhancer binding proteins (C/EBPs) are involved in the regulation of casein gene expression by mammary epithelial cells. Prolactin (Prl) activation of STAT5 is necessary for casein gene expression. The extracellular matrix (ECM) regulates also casein gene expression. Here, we have investigated whether ECM regulates C/EBPs activity in primary rabbit mammary epithelial cells. Isolated primary mammary cells were cultured on plastic or on floating collagen I gel. Prolactin induced ,s 1-casein gene expression when cells were cultured on collagen but not on plastic. It is noteworthy that activated STAT5 was detected in both culture conditions. Several STAT5 isoforms (STAT5a, STAT5b, and other STAT5 related isoforms, some with lower molecular weight than the full-length STAT5a and STAT5b) were detected under the different culture conditions. However, their presence was not related to the expression of ,s 1-casein gene. The binding of nuclear factors to a C/EBP specific binding site and the protein level of C/EBP, differed in cells cultured on plastic or on collagen but these parameters were not modified by Prl. This suggests that C/EBP binding activity was regulated by ECM and not by Prl. Interestingly, these modifications were correlated to the expression of the ,s 1-casein gene. Hence, the activation of the ,s 1-casein gene expression depends on two independent signals, one delivered by Prl via the activation of STAT5, the other delivered by ECM via C/EBP. J. Cell. Biochem. 82:371,386, 2001. © 2001 Wiley-Liss, Inc. [source]


    Central Administration of Orexin A Suppresses Basal and Domperidone Stimulated Plasma Prolactin

    JOURNAL OF NEUROENDOCRINOLOGY, Issue 12 2000
    S. H. Russell
    Abstract Orexin immunoreactive fibres are abundant in the hypothalamus suggesting a neuroendocrine regulatory role. Intracerebroventricular (ICV) administration of orexin A suppressed plasma prolactin in male rats by 71% at 20 min post-injection and 83% at 90 min post-injection (P < 0.005 vs saline at both time points). To investigate whether this effect was through the tuberoinfundibular dopaminergic (TIDA) system, a supra-maximal dose of domperidone, a dopamine receptor antagonist, was injected intraperitoneally (i.p.) prior to ICV injection of orexin A. ICV orexin A significantly suppressed domperidone (9 mg/kg)-stimulated plasma prolactin levels, by up to 40% (i.p. domperidone + ICV orexin A 3 nmol 34.5 ± 7.4 ng/ml and i.p. domperidone + ICV orexin A 20 nmol 43.5 ± 4.3 ng/ml, both P < 0.005 vs i.p. domperidone + ICV saline 57.9 ± 2.7 ng/ml). Orexin A, 100 nM, significantly stimulated release of neurotensin, vasoactive intestinal polypeptide, somatostatin, corticotropin releasing factor and luteinizing hormone releasing hormone, but had no effect on release of dopamine, thyrotropin releasing hormone (TRH), vasopressin or melanin-concentrating hormone from hypothalamic explants in vitro. Orexin A did not alter basal or TRH stimulated prolactin release in dispersed pituitary cells harvested from male rats. The data suggest that ICV administration of orexin A suppresses plasma prolactin in part through a pathway independent of the dopaminergic system. [source]


    Secretion of Prolactin and Growth Hormone in Relation to Ovarian Activity in the Dog

    REPRODUCTION IN DOMESTIC ANIMALS, Issue 3-4 2001
    HS Kooistra
    In pregnant bitches an apparent increase in plasma prolactin concentrations is observed during the second half of pregnancy, mean plasma prolactin concentrations peak on the day of parturition, fall for the next 24,48 h and then rise again. During lactation, high plasma prolactin concentrations are observed. Plasma prolactin levels in non-pregnant bitches appear to be lower than in pregnant animals, particularly in the last part of the luteal phase. Pulsatile secretion of prolactin has been observed during the luteal phase and mid-anoestrus. Progression of the luteal phase is found to be associated with an increase in prolactin release. The association of a strong increase of prolactin release and a decrease of plasma progesterone concentrations has also been demonstrated in overtly pseudopregnant bitches. Elevated prolactin secretion during progression of the luteal phase in the bitch may play a role in mammogenesis and is important because of the luteotrophic action of prolactin. Acromegaly is a syndrome of tissue overgrowth and insulin resistance due to excessive growth hormone (GH) production. In the bitch, acromegaly can be induced either by endogenous progesterone or by exogenous progestagens. Progestagen-induced GH production in this species originates from foci of hyperplastic ductular epithelium of the mammary gland. Pulsatile secretion of GH has been observed in normal cyclic bitches. In contrast with the pulsatile GH secretion seen in healthy dogs, the progestagen-induced plasma GH levels in bitches with acromegaly do not have a pulsatile secretion pattern. Just as with prolactin, the plasma progesterone levels influence the secretion pattern of GH in the bitch. The pulsatile secretion pattern of GH changes during the progression of the luteal phase in healthy cyclic bitches, with higher basal GH secretion and less GH being secreted in pulses during the first part of the luteal phase. The progesterone-induced GH production may promote the proliferation and differentiation of mammary gland tissue during the luteal phase of the bitch by local autocrine/paracrine effects and may exert endocrine effects. [source]


    Prolactin, Subjective Well-Being and Sexual Dysfunction: An Open Label Observational Study Comparing Quetiapine with Risperidone

    THE JOURNAL OF SEXUAL MEDICINE, Issue 12 2008
    Jens Westheide PhD
    ABSTRACT Introduction., Sexual dysfunction is a frequent side effect of antipsychotic treatment. Increased prolactin levels are believed to be responsible for this sexual impairment despite contradictory results. Aim., The primary objective of the present study was to examine the relationship between sexual dysfunction, subjective well-being and prolactin levels in patients with schizophrenia treated either with risperidone or quetiapine. The secondary objective was to explore the relationship between testosterone and the severity of positive and negative symptoms of schizophrenia in male patients. Methods., In a 4-week nonrandomized open label observational study, 102 inpatients with schizophrenia were recruited. Sexual functioning, subjective well-being and endocrinological parameters were assessed as well as psychopathological characteristics. Main Outcome Measures., Two self-rating questionnaires concerned with sexual functioning ("Essener Fragebogen zur Sexualität") and Subjective Well-Being Under Neuroleptic Treatment Scale (SWN) were completed by the patients. Plasma levels of prolactin in male and female patients were measured. Furthermore, in male patients testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were determined. Positive and Negative Symptom Scale (PANSS) was applied. Results., After 4 weeks, patients treated with quetiapine reported less severe sexual impairment, as well as lower PANSS negative and general score compared with patients treated with risperidone. Additionally, emotional regulation as measured with the SWN was higher in patients treated with quetiapine. Risperidone was significantly associated with elevated prolactin levels. Prolactin levels were not correlated either with sexual dysfunction or PANSS. However, in the group of patients treated risperidone, sexual impairment was significantly associated with the SWN subscale emotional regulation. Conclusions., Increased prolactin levels do not seem to be decisive for antipsychotic induced sexual dysfunction. Improvement of severity of illness and regaining the ability to regulate one's own emotion have positive influence on sexual functioning. Westheide J, Cvetanovska G, Albrecht C, Bliesener N, Cooper-Mahkorn D, Creutz C, Hornung W-P, Klingmüller D, Lemke MR, Maier W, Schubert M, Sträter B, and Kühn K-U. Prolactin, subjective well-being and sexual dysfunction: An open label observational study comparing Quetiapine with Risperidone. J Sex Med **;**:**,**. [source]


    S179D prolactin sensitizes human prostate cancer cells such that physiological concentrations of 1, 25 dihydroxy vitamin D3 result in growth inhibition and cell death

    THE PROSTATE, Issue 14 2007
    Wei Wu
    Abstract BACKGROUND S179D Prolactin (PRL) is a molecular mimic of naturally phosphorylated human PRL which has been shown to inhibit the growth of human prostate cancer cells both in vitro and when grown as tumors in nude mice. METHODS In the current study, we have investigated the potential interplay between S179D PRL and 1,25 dihydroxy vitamin D3 (1,25D) in the inhibition of prostate cancer cell growth by incubating cells under circumstances where each hormone alone has no effect. RESULTS Incubation of DU145 or PC3 cells in 100 pM 1,25D or 10 nM S179D PRL for 3 days showed no effect of each alone on expression of the vitamin D receptor (VDR), or the cell cycle regulatory protein p21, or on cell number. Incubation in both together increased expression of the VDR and p21 two to threefold. This co-operative effect was reproduced when activation of the p21 promoter was analyzed using a p21-luciferase (p21-luc) construct. Elimination of the VDR response element from p21-luc eliminated response to the hormone combination, showing that the effect on p21 was through the VDR. Most importantly, S179D PRL sensitized the cells to 1,25D such that there was a concentration-related reduction in cell number versus controls between 40 and 160 pM. At least part of this effect was via the induction of cell death. CONCLUSIONS These results suggest that combined anti-tumor therapy may be very efficacious and that the dose of 1,25D required may be below the range that results in hypercalcemia. Prostate 67: 1498,1506, 2007. © 2007 Wiley-Liss, Inc. [source]


    Prolactin alters the mechanisms of B cell tolerance induction

    ARTHRITIS & RHEUMATISM, Issue 6 2009
    Subhrajit Saha
    Objective Autoimmune diseases predominantly affect women, suggesting that female sex hormones may play a role in the pathogenesis of such diseases. We have previously shown that persistent mild-to-moderate elevations in serum prolactin levels induce a break in self tolerance in mice with a BALB/c genetic background. The aim of this study was to evaluate the effects of hyperprolactinemia on the mechanisms of B cell tolerance induction. Methods Effects of prolactin on splenic B cell subsets were studied in female BALB/c mice. B cell receptor (BCR),mediated apoptosis and proliferation of transitional B cells were analyzed by flow cytometry. Expression of apoptotic genes was examined by microarrays and real-time polymerase chain reaction analysis. B cells coexpressing ,/, light chains were assessed by flow cytometry and immunohistochemistry. Activation status of transitional type 3 (T3) B cells was evaluated by BCR-induced calcium influx studies. Results BCR-mediated apoptosis of the T1 B cell subset, a major checkpoint for negative selection of autoreactive specificities, was decreased in prolactin-treated mice. Microarray studies indicated that this event may be mediated by the prolactin-induced up-regulation of the antiapoptotic gene interferon-, receptor type II and down-regulation of the proapoptotic gene Trp63. Prolactin treatment also altered the amount of receptor editing, as indicated by the increased number of transitional B cells coexpressing ,/, light chains. Additionally, hyperprolactinemia modified the level of B cell anergy by increasing the degree of BCR-induced calcium influx in the T3 B cells. Conclusion Persistently elevated serum prolactin levels interfere with B cell tolerance induction by impairing BCR-mediated clonal deletion, deregulating receptor editing, and decreasing the threshold for activation of anergic B cells, thereby promoting autoreactivity. [source]


    Application of new homologous in vitro bioassays for human lactogens to assess the actual bioactivity of human prolactin isoforms in hyperprolactinaemic patients

    CLINICAL ENDOCRINOLOGY, Issue 2 2006
    Alfredo Leaños-Miranda
    Summary Background, ,Prolactin (PRL) plays a central role in mammary gland development and lactation. Due to its molecular heterogeneity, measurement of PRL immunoreactivity does not necessarily reflect its intrinsic bioactivity. For many years the Nb2 rat lymphoma cell bioassay has been the only reference bioassay for human lactogens. This bioassay, however, does not always correlate with the clinical features found in some patients exhibiting normal or elevated immunoreactive serum PRL concentrations. Objectives, ,(1) To determine the concentrations of bioactive PRL in serum samples from individuals with normoprolactinaemia or with different forms of hyperprolactinaemia using two recently described homologous in vitro bioassays (i.e. a transcriptional bioassay in HEK-293 cells and a proliferation assay in Ba/F3 cells); and (2) to compare these results with those generated by the classical Nb2 cell bioassay. Design, ,Cross-sectional study. Setting, ,An institutional biomedical research laboratory. Participants, ,Ten patients with symptomatic hyperprolactinaemia due to prolactinoma, 11 patients with asymptomatic hyperprolactinaemia and macroprolactinaemia, and nine normal women. Main outcome measures, ,Measurement of immunoreactive and bioactive concentrations of serum PRL. Results, ,Samples from normal women and patients with tumoral hyperprolactinaemia due to prolactinoma exhibited similar within-group concentration values of bioactive and immunoreactive serum PRL when tested by the three bioassays and the immunoradiometric assay employed. By contrast, measurement of bioactive PRL in samples from patients with macroprolactinaemia revealed that macroprolactin was poorly active in the homologous receptor bioassays, while it was more active in the Nb2 bioassay. Conclusions, ,The reduced bioactivity of PRL in patients with macroprolactinaemia may further explain the absence of clinical features of hyperprolactinaemia in these individuals. In addition, our findings indicate that species-specificity and sensitivity of the bioassays are determinant factors in the measurement of the intrinsic biological activity of circulating PRL. [source]


    Orexin receptor subtype activation and locomotor behaviour in the rat

    ACTA PHYSIOLOGICA, Issue 3 2010
    W. K. Samson
    Abstract Aim:, Orexin-producing neurones, located primarily in the perifornical region of the lateral hypothalamus, project to a wide spectrum of brain sites where they influence numerous behaviours as well as modulating the neuroendocrine and autonomic responses to stress. While some of the actions of orexin appear to be mediated via the type 1 receptor, some are not, including its action on the release of one stress hormone, prolactin. We describe here the ability of orexin to increase locomotor behaviours and identify the importance of both receptor subtypes in these actions. Methods:, Rats were tested for their behavioural responses to the central activation of both the type 1 (OX1R) and type 2 (OX2R) receptor (ICV orexin A), compared to OX2R activation using a relatively selective OX2R agonist in the absence or presence of an orexin receptor antagonist that possesses highest affinity for OX1R. Results:, Increases in locomotor activity were observed, effects which were expressed by not only orexin A, which binds to both the OX1R and the OX2R receptors, but also by the relatively selective OX2R agonist [(Ala11, Leu15)-orexin B]. Furthermore, the OX1R selective antagonist only partially blocked the action of orexin A on most locomotor behaviours and did not block the actions of [(Ala11, Leu15)-orexin B]. Conclusion:, We conclude that orexin A exerts its effects on locomotor behaviour via both the OX1R and OX2R and that agonism or antagonism of only one of these receptors for therapeutic purposes (i.e. sleep disorders) would not provide selectivity in terms of associated behavioural side effects. [source]


    Brain mechanisms underlying emotional alterations in the peripartum period in rats

    DEPRESSION AND ANXIETY, Issue 3 2003
    Inga D. Neumann
    Abstract In the period before and after parturition, i.e., in pregnancy and lactation, a variety of neuroendocrine alterations occur that are accompanied by marked behavioral changes, including emotional responsiveness to external challenging situations. On the one hand, activation of neuroendocrine systems (oxytocin, prolactin) ensures reproduction-related physiological processes, but in a synergistic manner also ensures accompanying behaviors necessary for the survival of the offspring. On the other hand, there is a dramatic reduction in the responsiveness of neuroendocrine systems to stimuli not relevant for reproduction, such as the hypothalamo-pituitary-adrenal (HPA) axis responses to physical or emotional stimuli in both pregnant and lactating rats. With CRH being the main regulator of the HPA axis, downregulation of the brain CRH system may result in various behavioral, in particular emotional, adaptations of the maternal organisms, including changes in anxiety-related behavior. In support of this, the lactating rat becomes less emotionally responsive to novel situations, demonstrating reduced anxiety, and shows a higher degree of aggressive behavior in the test for agonistic behavior as well as in the maternal defense test. These changes in emotionality are independent of the innate (pre-lactation) level of anxiety and are seen in both rats bred for high as well as low levels of anxiety. Both brain oxytocin and prolactin, highly activated at this time, play a significant role in these behavioral and possibly also neuroendocrine adaptations in the peripartum period. Depression and Anxiety 17:111,121, 2003. © 2003 Wiley-Liss, Inc. [source]


    Adipocyte prolactin: regulation of release and putative functions

    DIABETES OBESITY & METABOLISM, Issue 4 2007
    T. Brandebourg
    Pituitary-derived prolactin (PRL) is a well-known regulator of the lactating mammary gland. However, the recent discovery that human adipose tissue produces PRL as well as expresses the PRL receptor (PRLR) highlights a previously unappreciated action of PRL as a cytokine involved in adipose tissue function. Biologically active PRL is secreted by all adipose tissue depots examined: breast, visceral and subcutaneous. The expression of adipose PRL is regulated by a non-pituitary, alternative superdistal promoter. PRL expression and release increases during early pre-adipocyte differentiation and is stimulated by cyclic AMP activators, including , adrenergic receptor agonists. PRL release from subcutaneous adipose explants is attenuated during obesity, suggesting that adipose PRL production is altered by the metabolic state. Several lines of evidence indicate that PRL suppresses lipid storage as well as the release of adipokines such as adiponectin, interleukin-6 and possibly leptin. PRL has also been implicated in the regulation of adipogenesis. A newly developed PRL-secreting human adipocyte cell line, LS14, should allow comprehensive examination of the regulation and function of adipocyte-derived PRL. Collectively, these studies raise the prospect that PRL affects energy homeostasis through its action as an adipokine and is involved in the manifestation of insulin resistance. [source]


    Biomarker discovery in rat plasma for estrogen receptor-, action

    ELECTROPHORESIS, Issue 23 2005
    Tom G. Holt Dr.
    Abstract To support in vivo screening efforts for estrogen receptor (ER) subtype selective therapeutic agents, we initiated work to discover surrogate markers (biomarkers) in blood plasma that would change in response to ER subtype-specific action. We used a proteomic approach employing strong anion exchange chromatography (SAX), PAGE, and MS to identify potential plasma markers for selective ER-, action. The methodology was used to compare blood from vehicle-treated rats to blood from rats treated with either 17,-estradiol (an ER-,/ER-, agonist) or compound 1 (17,-ethynyl-[3,2-c]pyrazolo-19-nor-4-androstene-17,-ol, an ER-,-selective agonist). Blood samples were first fractionated by SAX to separate fractions containing dominant common plasma proteins from fractions enriched for less-abundant plasma proteins. 1-D PAGE analysis of fractions depleted of dominant plasma proteins revealed treatment-specific changes in protein profiles. Protein bands that changed reproducibly in response to ER-, action were excised from the gel, separated by capillary LC, and identified by microspray ESI-MS. Using this method, the plasma levels of two proteins, transthyretin and apolipoprotein E, were shown to decrease in response to ER-, agonism. The method lacked the sensitivity to identify the known, 1000-fold less-abundant, estrogenic marker prolactin (PRL). However, using a commercial RIA and immunoblots, we showed that PRL levels increase significantly in response to treatment with the ER-, selective agonist, compound 1. [source]


    RESEARCH FOCUS ON COMPULSIVE BEHAVIOUR IN ANIMALS: Pre-exposure to environmental cues predictive of food availability elicits hypothalamic,pituitary,adrenal axis activation and increases operant responding for food in female rats

    ADDICTION BIOLOGY, Issue 4 2009
    Carlo Cifani
    ABSTRACT The present study was undertaken to develop an animal model exploiting food cue-induced increased motivation to obtain food under operant self-administration conditions. To demonstrate the predictive validity of the model, rimonabant, fluoxetine, sibutramine and topiramate, administered 1 hour before the experiment, were tested. For 5 days, female Wistar rats were trained to self-administer standard 45 mg food pellets in one daily session (30 minutes) under FR1 (fixed ratio 1) schedule of reinforcement. Rats were then trained to an FR3 schedule and finally divided into two groups. The first group (control) was subjected to a standard 30 minutes FR3 food self-administration session. The second group was exposed to five presentations of levers and light for 10 seconds each (every 3 minutes in 15 minutes total). At the completion of this pre-session phase, a normal 30-minute session (as in the control group) started. Results showed that pre-exposure to environmental stimuli associated to food deliveries increased response for food when the session started. Corticosterone and adrenocorticotropic hormone plasma levels, measured after the 15-minute pre-exposure, were also significantly increased. No changes were observed for the other measured hormones (growth hormone, prolactin, thyroid-stimulating hormone, luteinizing hormone, insulin, amylin, gastric inhibitor polypeptide, ghrelin, leptin, peptide YY and pancreatic polypeptide). Rimonabant, sibutramine and fluoxetine significantly reduced food intake in both animals pre-exposed and in those not pre-exposed to food-associated cues. Topiramate selectively reduced feeding only in pre-exposed rats. The present study describes the development of a new animal model to investigate cue-induced increased motivation to obtain food. This model shows face and predictive validity, thus, supporting its usefulness in the investigation of new potential treatments of binge-related eating disorders. In addition, the present findings confirm that topiramate may represent an important pharmacotherapeutic approach to binge-related eating. [source]


    CLINICAL STUDY: Prolactin response to fenfluramine in abstinent, alcohol-dependent patients

    ADDICTION BIOLOGY, Issue 3-4 2008
    Richard J. Porter
    ABSTRACT It has been suggested that serotonin (5HT) function is abnormal in alcoholics even during abstinence. The prolactin response to fenfluramine (PRF) is generally believed to reflect the activity of the 5HT system and has been previously used to investigate 5HT activity in a variety of conditions, including alcoholism. The origin of the cortisol (CORT) response to fenfluramine is less clear. The objectives of this paper are to examine the prolactin (PRL) and CORT response to dl -fenfluramine in a large cohort of males with alcohol dependence who had been abstinent for 3 weeks, and to compare this with an age-matched control group. Ninety-four subjects with a DSM-III-R diagnosis of moderate to severe alcohol dependence who had been abstinent for 3 weeks, and 23 control subjects underwent neuroendocrine challenge with dl -fenfluramine (10 mg per 10 kg body weight). PRL and CORT responses were measured. No significant difference was found in PRF between abstinent, alcoholic patients and controls (F = 2.7, d.f. = 1.115, P = 0.10). CORT response was significantly lower in abstinent alcoholics than in controls (F = 10.0, d.f. = 1.116, P = 0.002). The results suggest no clear difference in 5HT function between abstinent alcoholics and healthy controls. The reduced CORT response in abstinent alcoholics further supports evidence of hypofunction of the adrenocortical system in this group. [source]


    Chronic cognitive sequelae after traumatic brain injury are not related to growth hormone deficiency in adults

    EUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2010
    D. Pavlovic
    Objective:, The objective of the study was to asses the possible influence of hypothalamo,pituitary deficiencies, and growth hormone (GH) deficiency in particular, on cognition in adult patients with traumatic brain injury (TBI). TBI is a recently identified risk factor for cognitive deficits and hypopituitarism. Even the patients with favorable outcome after TBI may present with persistent bodily, psychosocial, and cognitive impairments, resembling patients with untreated partial or complete pituitary insufficiency. Design:, We performed retrospective and cross-sectional study of endocrine and cognitive function in TBI in 61 patients (aged 37.7 ± 1.7 years) of both sexes (44 m,17 f), at least 1 year after TBI (3.9 ± 0.6 years). Serum insulin-like growth factor 1 (IGF-I), thyroxin, thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (in men), prolactin, and cortisol were measured, and GH secretion was assessed by growth hormone releasing hormone (GHRH) + growth hormone releasing peptide-6 (GHRP-6) test. Cognitive function was assessed by using a standard neuropsychological battery. Results:, GH deficiency (GHD) and GH insufficiency (GHI) were found in 20 patients (32.8%). After adjustment for confounders [age, body mass index (BMI), education level, time elapsed from TBI], there were no significant differences in results of neuropsychological tests between patients with TBI with GHD, GHI, and normal GH secretion. There were no correlations of neuropsychological variables with stimulated peak GH secretion or IGF-I level. Conclusions:, GHD persists long after the TBI, independently of trauma severity and age at traumatic event. GH secretion is more sensitive to TBI than other pituitary hormones. No evidence is found for an association of cognitive function impairment and somatotropic axis impairment in adult patients tested more than 1 year after the TBI. [source]


    N -methyl-1-(1,3-benzodioxol-5-yl)-2-butanamine (MBDB): its properties and possible risks

    ADDICTION BIOLOGY, Issue 3 2000
    L. A. G. J. M. Van Aerts
    MBDB (N -methyl-1-(1,3-benzodioxol-5-yl)-2-aminobutane) is the ,-ethyl homologue of MDMA (3,4-methylenedioxy-N-methylamphetamine). MBDB is metabolized and excreted similarly to MDMA: presumably, the majority of oral MBDB is excreted in urine unmetabolized. The main metabolic routes in man are thought to be O-dealkylation and subsequent methylation, sulphation and glucuronidation of the newly formed hydroxy groups. The major acute neuropharmacological effects of MBDB in the rat are an increase in serotonin release in the brain and an inhibition of serotonin and noradrenaline re-uptake. These effects compare well with those of MDMA, although the latter is more potent. MBDB may also slightly increase dopamine release and inhibit dopamine re-uptake, but to a lesser extent than MDMA. This is important, as dopamine release has been implicated in the reinforcing qualities of substances such as cocaine and amphetamine. The neuroendocrine effects of MBDB resemble those of MDMA. Both substances increase plasma ACTH, corticosterone, prolactin and renin. The neurophysiological effects of MBDB are characterized by a decrease in electrical activity throughout the brain, most notably in the alpha 2 and delta frequency bands. In contrast, hallucinogens increase the activity in the alpha 1 band, especially in the corpus striatum. In drug discrimination tests in the rat, MBDB, like MDMA, can be distinguished clearly from both stimulants and hallucinogens. The class of substances to which MBDB belongs may be named entactogens. MBDB dose-dependently increases locomotor activity and decreases exploratory behaviour in the rat and causes distress vocalization and wing extension in the newly hatched chicken. The rewarding properties of MBDB appear to be smaller than those of MDMA, as suggested by a 2.5 times weaker potency in the conditioned place preference test in rats. The main subjective effects of MBDB in man are a pleasant state of introspection, with greatly facilitated interpersonal communication and a pronounced sense of empathy and compassion between subjects. In this respect, MBDB again resembles MDMA. However, there are also differences. MBDB has a slower and more gentle onset of action than MDMA, produces less euphoria and has less stimulant properties. The few toxicological data available suggest that MBDB may cause serotonergic deficits in the brain, although the potency of MBDB to cause this neurotoxic effect is smaller than that of MDMA. Severe acute reactions in man as have been reported for MDMA have not been published for MBDB. The dependence potential of MBDB appears to be small, probably even smaller than that of MDMA. MBDB has been available at least since 1994 but its position on the synthetic drugs market is marginal. Subjective reports indicate that MBDB is less popular among users than MDMA. The reason may be that MBDB produces less euphoria than MDMA. Another possible explanation is that MBDB largely lacks the stimulant properties of MDMA. We calculated a margin of safety with a method similar to one used in the risk assessment of pharmaceuticals. The results suggest that MBDB is three times less likely to cause serotonergic brain deficits than MDMA. However, it should be noted that for both substances the margin of safety is less than one, indicating that the risk of neurotoxicity is not negligible. In animals, serotonergic brain deficits after exposure to MDMA have been linked to the degeneration of serotonergic nerve terminals. [source]


    Effects of prolactin on intracellular calcium concentration and cell proliferation in human glioma cells

    GLIA, Issue 3 2002
    Thomas Ducret
    Abstract Prolactin (PRL) has several physiological effects on peripheral tissues and the brain. This hormone acts via its membrane receptor (PRL-R) to induce cell differentiation or proliferation. Using reverse transcription,polymerase chain reaction (RT-PCR) combined with Southern blot analysis, we detected PRL-R transcripts in a human glioma cell line (U87-MG) and in primary cultured human glioblastoma cells. These transcripts were deleted or not in their extracellular domains. We examined the effects of PRL on intracellular free Ca2+ concentration ([Ca2+]i) in these cells in order to improve our understanding of the PRL transduction mechanism, which is still poorly documented. [Ca2+]i was measured by microspectrofluorimetry using indo-1 as the Ca2+ fluorescent probe. Spatiotemporal aspects of PRL-induced Ca2+ signals were investigated using high-speed fluo-3 confocal imaging. We found that physiological concentrations (0.4,4 nM) of PRL-stimulated Ca2+ entry and intracellular Ca2+ mobilization via a tyrosine kinase,dependent mechanism. The two types of Ca2+ responses observed were distinguishable by their kinetics: one showing a slow (type I) and the other a fast (type II) increase in [Ca2+]i. The amplitude of PRL-induced Ca2+ increases may be sufficient to provoke several physiological responses, such as stimulating proliferation. Furthermore, PRL induced a dose-dependent increase in [3H]thymidine incorporation levels and in cellular growth and survival, detected by the MTT method. These data indicate that PRL induced mitogenesis of human glioma cells. GLIA 38:200,214, 2002. © 2002 Wiley-Liss, Inc. [source]


    The effect of sexual hormone abnormalities on proximal femur bone mineral density in hemodialysis patients and the possible role of RANKL

    HEMODIALYSIS INTERNATIONAL, Issue 1 2008
    Konstantinos K. DOUMOUCHTSIS
    Abstract Sexual hormone concentrations are commonly affected in chronic renal failure. The contribution of sex steroids to bone turnover regulation implies that sex steroid's dysfunction may be implicated in the emergence of renal osteodystrophy. This study was conducted to evaluate sex steroids and gonadotrophins in hemodialysis (HD) patients and to investigate their role in bone homeostasis in concert with other hormones and cytokines. Bone mineral density (BMD) at the proximal femur and intact parathyroid hormone (iPTH), osteoprotegerin, soluble receptor activator of NF-,B ligand (sRANKL), prolactin, total testosterone, estradiol, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were measured in serum samples in 42 patients, 21 men and 21 women, on maintenance HD therapy. Possible associations between clinical characteristics, biochemical parameters, and BMD values were investigated. In male HD patients, the testosterone concentration declined significantly with aging, whereas the estradiol level increased with longer duration of HD. Concurrently, testosterone correlated negatively with sRANKL concentrations (r=,0.520, p=0.016). Luteinizing hormone levels in male patients demonstrated statistically significant negative correlations with BMD values of the proximal femur. In the entire cohort of patients, FSH and LH were negatively associated with absolute values of proximal femur BMD. Gonadotrophin and sexual hormone concentrations in HD patients are associated with bone mineral status and consequently their derangements appear to contribute to the development of bone composition abnormalities in different types of renal osteodystrophy. Furthermore, testosterone's association with sRANKL levels in male HD patients suggests that RANKL may mediate the effect of testosterone on bone metabolism in these patients. [source]


    Effects of long-term exposure to ramelteon, a melatonin receptor agonist, on endocrine function in adults with chronic insomnia

    HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 2 2009
    Gary Richardson
    Abstract Objective To evaluate the effects of ramelteon, an MT1/MT2 melatonin receptor agonist used to treat insomnia, on endocrine function in adults with chronic insomnia. Methods This was a double-blind, placebo-controlled, trial of adults (18,45 years) with chronic insomnia. Subjects received either ramelteon 16,mg or placebo nightly for 6 months. Hormonal measures of the thyroid, reproductive, and adrenal axes were analyzed monthly and compared with baseline and placebo values. Results While isolated changes were detected at some time points, there were no consistent statistically significant differences between treatments on measures of thyroid function (total T4, free T4, TSH, and total T3), adrenal function (AM cortisol, and ACTH), or on most reproductive endocrine measures [LH, FSH, estradiol (women), total, and free testosterone (men)]. Prolactin concentrations were increased overall in women in the ramelteon group compared with placebo (p,=,0.003). No clinical effects of elevated prolactin were reported; average menstrual cycle length, duration of menses, and ovulation probability did not differ between groups. Conclusions Long-term exposure to ramelteon 16,mg, a potent melatonin receptor agonist, resulted in mild, transient increase in prolactin, in women only, that were not associated with measurable reproductive effects. There were no consistent changes in other endocrine measures. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    Effectiveness of antipsychotic polypharmacy for patients with treatment refractory schizophrenia: an open-label trial of olanzapine plus risperidone for those who failed to respond to a sequential treatment with olanzapine, quetiapine and risperidone

    HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 6 2008
    Takefumi Suzuki
    Abstract Objective To evaluate the effectiveness of antipsychotic polypharmacy in a methodologically sound manner. Methods In this open-label study, 17 patients with treatment-refractory schizophrenia, who failed to respond to a sequential monotherapy with olanzapine, quetiapine and risperidone, were subsequently treated with a combination therapy with olanzapine plus risperidone for at least 8 weeks. Results Seven responded according to the primary endpoint defined as the post-treatment Brief Psychiatric Rating Scale being less than 70% of the pretreatment values, and they were classified as such an average of 10 weeks after the initiation of polypharmacy. Two of them were successful in a later conversion to monotherapy. None dropped out prematurely. Four (out of 13 inpatients) got better enough to be discharged from the hospital, while six patients did not show any response. The Global Assessment of Functioning score improved from 37.1 to 53.0 in responders (mean maximum dose: olanzapine 12.9,mg; risperidone 3.14,mg), while it showed non-significant changes among others (mean maximum dose: olanzapine 14.5,mg; risperidone 5.50,mg). Body weight, prolactin, and total cholesterol increased significantly. Conclusions Antipsychotic polypharmacy might be sometimes helpful for difficult populations but at the cost of adverse effects. More studies of antipsychotic combination therapy versus clozapine, augmentation strategies or tenacious longer- term monotherapy are warranted for refractory schizophrenia. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    Relationship of prolactin response to meta-chlorophenylpiperazine with severity of drug use in cocaine dependence

    HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 6 2006
    Ashwin A. Patkar
    Abstract Rationale Serotonergic (5-HT) mechanisms appear to mediate central effects of cocaine. Therefore 5-HT disturbances could be associated with drug severity. Objectives We investigated whether prolactin (PRL) response to meta-chlorophenylpiperazine (m-CPP), a mixed 5-HT agonist/antagonist were associated with severity of cocaine use. Methods Thirty-six cocaine-dependent subjects and 33 controls underwent a challenge with 0.5,mg/kg of oral m-CPP. Severity of drug use was assessed using the Addiction Severity Index (ASI). Results The PRL response to m-CPP was significantly blunted in cocaine patients compared to controls (F,=,21.86, p,<,0.001). ,PRL (peak PRL,baseline PRL) was negatively correlated with ASI-drug (r,=,,0.45, p,<,0.01), ASI-alcohol (r,=,,0.32, p,<,0.05), and ASI-psychological (r,=,,0.41, p,<,0.01) composite scores, and with the quantity, frequency and duration of drug use (r ranged from ,,0.41 to ,,0.32, p ranged from <,0.01 to 0.05). Hierarchical regressions showed that ASI-drug composite scores significantly predicted the variance in ,PRL after controlling for behavioral and demographic variables (F,=,4.27, p,<,0.05). Conclusions The results indicate that disturbances in 5-HT function as reflected by a blunted response to m-CPP seem to be primarily associated with severity of drug use and to a lesser, although significant extent with behavioral traits in cocaine-dependent patients. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Dopamine challenge tests as an indicator of psychological traits

    HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 2 2006
    P. Netter
    Abstract After discussing some introductory considerations about the value of challenge tests in general for discriminating personality dimensions which are considered extrapolations of psychopathological diseases, the present paper outlines the matter of responsivity to agonistic and antagonistic dopaminergic drugs or drugs of different mechanisms of action in the dopaminergic system, and elucidates that different hormones elicited by dopaminergic substances (prolactin, growth hormone) may indicate personality related differences in susceptibility of different brain areas. A further point was to demonstrate not only the well known relationship of dopaminergic hyperactivity with reward seeking and motivational factors associated with extraversion and novelty seeking, but also the relationship of dopaminergic hypofunction with the personality dimension of depression which had already been reported in studies on animals and psychiatric patients. A final point was to demonstrate that besides size of hormone responses additional parameters like time of response onset and initial prolactin increase can be used as biochemical indicators for identifying certain personality types, like highly depressive neurotic persons characterized by lower and later dopamine responses as compared to low depressives, and extraverted sensation-seeking types responding by an initial prolactin peak as opposed to low sensation seekers. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Relations of clinical features, subgroups and medication to serum monoamines in schizophrenia

    HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 1 2002
    Robert D. Oades
    Abstract Background Plasma and serum indices of monoaminergic activity reflect partly the illness of schizophrenia (e.g. HVA/deficit syndrome) and sometimes the symptoms (e.g. HVA/anhedonia). But, such studies have rarely taken both metabolites and parent amines or inter-amine activity ratios into account. We hypothesized that comparing the major symptom dimensions to measures of transmitter activity (with and without control for antipsychotic drug treatment) would show differential patterns of activity useful for the design of pharmacological treatments. Methods Dopamine (DA), noradrenaline (NA), serotonin (5-HT), their three major metabolites and prolactin were measured in the serum of 108 patients with schizophrenia and 63 matched controls: DA D2-receptor blocking-activity was estimated from a regression of butyrophenone displacement in striatum in vitro on to PET reports of drug-binding in vivo. Symptoms were factored into four dimensions (disorganized/thought disorder, nonparanoid/negative, ideas-of-reference and paranoid/positive symptoms). Results (1) Patients' DA activity did not differ from controls: but their 5-HT and NA turnovers increased/decreased, respectively, and the DA/5HT-metabolite ratio was lower. Increased DA-D2-receptor occupancy was predicted by decreased DA-metabolism and its ratio to 5-HT-metabolism. (2) Patients had higher levels of NA, DA-metabolites and DA-/5-HT-metabolite ratios on atypical vs typical drugs. (3) Increased D2-occupancy was associated with lower DA metabolism in paranoid patients but was unrelated to relative increases of DA/5-HT- and NA-metabolism in nonparanoid patients. (4) Low DA-/5-HT-metabolite ratios, high prolactin and low DA-metabolism characterized thought-disordered patients. (5) High DA-/5-HT-metabolite ratios paralleled many ideas-of-reference. The metabolites were sensitive, respectively, to control for D2-occupancy and prolactin. Conclusions The role of DA in paranoid, and 5-HT in thought-disordered and ideas-of-reference dimensions point both to the mechanisms underlying the features typical of these subgroups and the type of medication appropriate. Copyright © 2002 John Wiley & Sons, Ltd. [source]


    The impotent couple: low desire

    INTERNATIONAL JOURNAL OF ANDROLOGY, Issue 2005
    G. CORONA
    Summary Hypoactive sexual desire (HSD) is the deficiency of sexual fantasies and desire that should be considered as a disorder if it causes distress to the couple. In the general population, it is the most widespread sexuality-related problem. It is generally accepted that testosterone and prolactin regulate sexual desire. We recently reported that other psychobiological factors associate with HSD in a sample of almost 500 male patients attending our Outpatient Clinic for sexual dysfunction, by using SIEDY structured interview. We now originally extend investigation to a threefold broader patient sample. Considering marital parameters, perceived partner's libido and climax, patient's partner diseases, conflictual or even prolonged couple relationship were all significantly associated with an impairment of patients' sexual desire. Moreover, other lifestyle factors as satisfaction at work and/or domestic inhabitant relationship were significantly correlated to hypoactive sexual desire disorder (HSDD). Among hormonal parameters, severe hyperprolactinaemia (>700 mU/L), although rarely diagnosed (<2.0%), seems to play a greater role than the more common (23%) endocrine disease hypogonadism (testosterone < 12 nm) to the pathogenesis of HSD (RR = 7.5 [2.5,22.4] vs. 1.5 [1.1,1.9], respectively). Both mental disorders and use of medication interfering with sexual function were also significantly associated with HSDD, as well as depressive and anxiety symptoms. Finally, HSD was inversely correlated to sexual and masturbation frequency attempts. In conclusion, HSD is associated with several biological, psychological, and relational factors that can be simultaneously identified and quantified using the SIEDY structured interview. [source]


    Endogenous sex hormones, prolactin and mammographic density in postmenopausal Norwegian women

    INTERNATIONAL JOURNAL OF CANCER, Issue 11 2007
    Yngve Bremnes
    Abstract The associations between endogenous sex hormone levels and breast cancer risk in postmenopausal women are well established. Mammographic density is a strong risk factor for breast cancer, and possibly an intermediate marker. However, the results from studies on the associations between endogenous sex hormones and mammographic density are conflicting. The authors examined the associations between circulating levels of sex hormones, sex hormone binding globulin (SHBG) and prolactin and mammographic densities among postmenopausal women not currently using postmenopausal hormone therapy (HT). The authors also examined if insulin-like growth factor-I (IGF-I) levels influenced the association between estrogen and mammographic density. Altogether, 722 postmenopausal participants in the Norwegian governmental mammographic screening program had endogenous hormone concentrations measured. Mammograms were classified according to percent and absolute mammographic density using a previously validated computer-assisted method. After adjustment for age, number of children, age at menopause, body mass index and HT use, both plasma concentrations of SHBG (p -trend = 0.003) and estrone (p -trend = 0.07) were positively associated with percent mammographic density. When the analyses were stratified according to median IGF-I concentration, the weak association between estrone and mammographic density was strengthened among women with IGF-I levels below median, while the association disappeared among women with over median IGF-I levels (p for interaction = 0.02). In summary, the authors found a positive association between plasma SHBG levels and mammographic densities among 722 postmenopausal Norwegian women not currently using HT. Further, the authors found a positive but weak association between plasma estrone concentration and mammographic density, which appeared to be modified by IGF-I levels. © 2007 Wiley-Liss, Inc. [source]


    Prolactin and macroprolactin in patients with systemic lupus erythematosus

    INTERNATIONAL JOURNAL OF RHEUMATIC DISEASES, Issue 3 2008
    Mohammadhassan JOKAR
    Abstract Aim: The aim of this study was to evaluate plasma levels of prolactin and macroprolactin in a group of systemic lupus erythematosus (SLE) patients and to determine if prolactin and macroprolactin concentrations were related to disease activity, clinical features or serological abnormalities. Methods: Ninety consecutive Iranian patients with SLE were tested for serum prolactin and macroprolactin levels. Total prolactin was measured directly in serum samples by radioimmunoassay. Free prolactin was extracted from the serum using polyethylene glycol. Clinical manifestation and SLE disease activity index (SLEDAI) were recorded. Auto antibodies were determined by standard techniques. Results: There were 90 patients (7 male, 83 female) with a mean age of 27.6 ± 9.1 (range 14,52). The mean disease duration was 27.6 ± 9.1 months. The frequency of high prolactin and macroprolactin, respectively, was 10% (9/90) and 5.6% (5/90) in patients with SLE. Macroprolactinemia was found in 55.55% (5/9) of hyperprolactinemic patients. Lupus activity was present in 63.3% (57/90) of patients without a significant difference in the frequency of high serum prolactin and macroprolactin levels when compared to inactive lupus. There were no statistically significant differences regarding demographic, clinical and laboratory characteristics between the group of patients with macroprolactinemia and the group without macroprolactinemia. Conclusion: Our results suggest that a subgroup of SLE patients have hyperprolactinemia and macroprolactinemia but they do not seem to have positive or negative correlation to clinical and laboratory features and disease activity. [source]


    Plasma progesterone, oestradiol-17, and total oestrogen profiles in relation to oestrous behaviour during induced ovulation in Murrah buffalo heifers

    JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 4 2009
    K. S. Roy
    Summary The objectives of this study were to establish the characteristics of oestrous behaviour in Ovsynch (induction of ovulation through administration of GnRH-PGF2, -GnRH in a systemic manner on 0, seventh and ninth day respectively) and Ovsynch plus Norprolac (Quinagolide hydrochloride , an inhibitor of prolactin secretion) treated Murrah buffalo heifers and to determine the relationships between this behaviour and the plasma concentrations of oestradiol-17, (E2), total oestrogen, and progesterone. Oestrus was detected by visual observations of oestrus signs, per rectal examination of genitalia and bull parading thrice a day during treatment period. Among all the symptoms, it was observed that bull mounting of heifers in oestrus was highest. Examination of genital tracts per rectum revealed that the cervix was relaxed, uterus was turgid and ovaries had palpable follicle in animals with oestrus. The peak concentrations of E2 (10.81 ± 0.62 pg/ml) and total oestrogen (17.11 ± 1.21 pg/ml) occurred at 9.45 ± 0.85 and 9.64 ± 0.93 h after second GnRH administration, respectively, in Ovsynch treated animals. However, the peak levels of E2 (20.02 ± 2.87 pg/ml) and total oestrogen (32.71 ± 3.15 pg/ml) occurred at 10.18 ± 0.50 and 10.36 ± 0.75 h after second GnRH administration, respectively, in Ovsynch plus Norprolac treated animals. Plasma progesterone concentration was basal (0.20 ± 0.001 ng/ml) during the peri-oestrus period. The plasma progesterone concentration was the lowest on the day of oestrus and increased to register a peak on day 13 ± 2 of the cycle. Oestrous behaviour was positively correlated with the peak concentration of E2 (p < 0.001) and total oestrogen (p < 0.001) during the peri-oestrus period. Inhibition of prolactin by Norprolac administration significantly increased the concentration of E2 and total oestrogen during oestrus in buffaloes in comparison to those recorded in animals subjected to Ovsynch protocol alone. In conclusion, our results suggest that the peak concentrations of E2 and total oestrogen and mean level of E2 and total oestrogen during the peri-oestrus period are the important factors contributing the behavioural manifestation of oestrus in buffalo cows. [source]


    Modular changes of cis-regulatory elements from two functional Pit1 genes in the duplicated genome of Cyprinus carpio

    JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2006
    G. Kausel
    Abstract The pituitary-specific transcription factor Pit1 is involved in its own regulation and in a network of transcriptional regulation of hypothalamo-hypophyseal factors including prolactin (PRL) and growth hormone (GH). In the ectotherm teleost Cyprinus carpio, Pit1 plays an important role in regulation of the adaptive response to seasonal environmental changes. Two Pit1 genes exist in carp, a tetraploid vertebrate and transcripts of both genes were detected by RT-PCR analysis. Powerful comparative analyses of the 5,-flanking regions revealed copy specific changes comprising modular functional units in the naturally evolved promoters. These include the precise replacement of four nucleotides around the transcription start site embedded in completely conserved regions extending upstream of the TATA-box, an additional transcription factor binding site in the 5,-UTR of gene-I and, instead, duplication of a 9 bp element in gene-II. Binding of nuclear factors was assessed by electro mobility shift assays using extracts from rat pituitary cells and carp pituitary. Binding was confirmed at one conserved Pit1, one conserved CREB and one consensus MTF1. Interestingly, two functional Pit1 sites and one putative MTF1 binding site are unique to the Pit1 gene-I. In situ hybridization experiments revealed that the expression of gene-I in winter carp was significantly stronger than that of gene-II. Our data suggest that the specific control elements identified in the proximal regulatory region are physiologically relevant for the function of the duplicated Pit1 genes in carp and highlight modular changes in the architecture of two Pit1 genes that evolved for at least 12 MYA in the same organism. J. Cell. Biochem. 99: 905,921, 2006. © 2006 Wiley-Liss, Inc. [source]


    Effect of aging on corticosterone secretion in diestrous rats

    JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2006
    Ming-Jae Lo
    Abstract The roles of age and prolactin (PRL) in regulating glucocorticoid secretion in diestrous rats were investigated. Adrenal zona fasciculata-reticularis (ZFR) cells from young, adult, middle (mid)-aged, and old female rats were isolated. Estrous cycle stage was determined by light microscopy after vaginal smears. Blood samples were collected from right jugular vein at 0, 30, 60, and 120 min after challenge with adrenocorticotropin (ACTH). During the diestrous phase, plasma levels of estradiol and progesterone were lower in mid-aged and old rats than in either young or adult rats. Age-dependent increases of the basal levels of plasma PRL and corticosterone were observed. No difference of ACTH-increased plasma concentrations of corticosterone was observed among young, adult, mid-aged, and old rats. Aging increased the basal, ACTH-, PRL-, forskolin (an adenylate cyclase activator)-, and 3-isobutyl-l-methylxanthine (IBMX, a non-selective phosphodiesterase inhibitor)-stimulated release of corticosterone and production of adenosine 3,, 5,-cyclic monophosphate (cAMP) in ZFR cells. However, the 8-Br-cAMP (a membrane-permeable cAMP)-stimulated release of corticosterone was not affected by age. Taken together, these data indicated that aging increased corticosterone secretion in female rats during diestrous phase, which is in part due to an increase in cAMP accumulation. In conclusion, aging and PRL play a stimulatory role in the co-regulation of corticosterone secretion. J. Cell. Biochem. © 2005 Wiley-Liss, Inc. [source]