Role Of Prolactin Research Articles

Prolactin Role in COVID-19 and Its Association with the Underlying Inflammatory Response

The COVID-19 pandemic has prompted interest in identifying reliable biomarkers to predict disease severity and guide clinical decisions. Prolactin (PRL), a hormone traditionally associated with lactation, has gained attention for its role in immune modulation. This study aimed to assess PRL as a biomarker for disease severity in COVID-19. A prospective cohort of 142 patients with moderate to severe COVID-19, defined as a WHO-CPS 5 or 6, was recruited from the University General Hospital of Patras. Baseline PRL levels were measured using an electrochemiluminescence immunoassay, and serum cytokines, including IL-1β, IL-6, IL-8, IL-10, IL-12p70, and TNF-α, were quantified through flow cytometry. Clinical outcomes, including mortality and the need for invasive mechanical ventilation (IMV), were recorded. Results indicated that PRL levels were significantly higher in female patients (12.95 ng/mL vs. 9.40 ng/mL, p < 0.001) but they did not correlate with key severity indices such as CCI, SOFA score upon admission or inflammatory markers. No significant associations between baseline PRL levels, cytokine concentrations, and clinical outcomes in COVID-19 were noted. Our findings suggest that PRL may lack prognostic reliability for disease severity compared to more established predictive markers and that its role in the immune response remains uncertain.

Breastfeeding in patients with peripartum cardiomyopathy: clinical outcomes and physician counseling

BackgroundPeripartum cardiomyopathy (PPCM) is a form of heart failure occurring towards the end of pregnancy or in the months following delivery. Concerns regarding the role of prolactin (the polypeptide hormone responsible for lactation) driving the pathogenesis of PPCM have led experts to discourage patients from breastfeeding; however, limited clinical data exist. We sought to (1) determine whether lactation was associated with less cardiac recovery and (2) assess the counseling about breastfeeding given to patients at the time of their initial diagnosis.MethodsPatients diagnosed with PPCM from 1999 to 2019 were identified through detailed chart review and demographic characteristics, comorbidities, outcomes, and lactation status were collected. Cardiac recovery was defined as left ventricular ejection fraction (LVEF) 55% or higher. A survey about breastfeeding and patient experience was administered by mail. Patients were only included in this analysis if definitive information about lactation status was documented.ResultsOf 220 patients with confirmed PPCM, lactation status was known definitively in 54 patients; of these, 18 (33%) had breastfed for at least 6 weeks and 36 (67%) did not breastfeed. There were no significant differences in the breastfeeding and non-breastfeeding groups related to baseline LVEF, age, race, gestational diabetes, smoking, hypertensive disorders of pregnancy, and medication treatments. Despite similar baseline LVEF at the time of diagnosis, there was no statistically significant difference in cardiac recovery based on lactation status. In a subset of patients with severe cardiac dysfunction at the time of diagnosis, there remained no significant differences in recovery based on lactation status. Of the 34 survey respondents, 62% were told not to breastfeed due to their diagnosis or concerns regarding safety of medications, and none were encouraged to breastfeed.ConclusionIn this retrospective cohort, lactation was not associated with lower rates of myocardial recovery. Importantly, a majority of patients had received counseling that they should not breastfeed. Future studies of the role of lactation in PPCM are needed in order to better understand the impact of breastfeeding and improve patient counseling.

The homeo-FIT-prolactin hypothesis: the role of prolactin in metabolic homeostasis - association or causality?

The homeo-fit-prolactin hypothesis proposes a causal metabolic role for prolactin with hypoprolactinemia and hyperprolactinemia leading to adverse metabolic alterations. However, prolactin within the normal range and up to four times the upper reference limit may be a consequence of metabolic adaption and have a positive metabolic role similar to increased insulin in pre-diabetes. As a consequence, drugs that would increase prolactin levels within this threshold may hold promising effects, particularly for patients with type 2 diabetes. A documented positive metabolic effect of prolactin just above the normal threshold would not just be of benefit to patients with diabetes but assist in the decision to treat mild hyperprolactinemia in other patient groups as well, e.g. drug-induced hyperprolactinemia or idiopathic hyperprolactinemia. Prolactin receptors are present in the pancreas, liver, and adipose tissue, and pre-clinical studies suggest a positive and causal effect of prolactin on the gluco-insulinemic profile and lipid metabolism. This narrative review examines the evidence for the homeo-fit-prolactin hypothesis with a particular focus on results from human studies.

Osmoregulation and reproduction: evolutionary trends in prolactin functions from fish to mammals

The study of prolactin function evolution provides key insights into the diverse effects of this hormone in mammals, both in health and disease, which is relevant from both theoretical and practical perspectives. This article reviews both original and literature data concerning the role of prolactin and its receptors in regulating the sexual dimorphism of freshwater adaptation in the three-spined stickleback Gasterosteus aculeatus L. It is demonstrated that mRNA expression of prolactin gene 1 (one of two prolactin paralogs) and its receptor PRLRA increases in the brains of female sticklebacks only upon transitioning to freshwater. The brain and kidneys of sticklebacks, as androgen-dependent organs, exhibit sex-dependent expression of Prlra in seawater. It is suggested that sex-dependent osmoregulatory effects of prolactin are mediated through the PRLRA receptor in these organs. The PRLRB receptor, expressed in the kidneys and brains of sticklebacks regardless of sex in seawater, shows increased sensitivity to reduced salinity, suggesting a more active role in implementing sex-independent osmoregulatory functions of prolactin. Gills and intestines, as osmoregulatory organs, express the PRLRA and PRLRB receptors independent of sex in both seawater and freshwater. With freshwater adaptation, there is a concurrent increase in the expression of Prl1 in the brains of females and the expression of Atp1a1 (α1a subunit of Na+/K+-ATPase), Nhe3 (NHE3 sodium-proton antiport gene), and Ecac (epithelial calcium channel gene) in their gills. It is presumed that these gill genes are under positive control by prolactin. Exploring the potential for prolactin’s osmoregulatory function in mammals revealed that it may manifest in conditions such as pathologies accompanied by increased expression of prolactin receptor isoforms in osmoregulatory organs. One of such pathologies is cholestasis in female rats, which was associated with an increase in Prlr isoform expression and changes in activity and ratio of Na+/K+-ATPase subunits in the kidney. Thus, it is concluded that in fish, the osmoregulatory function of prolactin is sex-dependent, while in mammals, it may manifest under conditions of disrupted water-salt exchange.

Prolactin and Hyperprolactinaemia in Endometriosis-Related Infertility: Are There Clinically Significant Connections?

Endometriosis and hyperprolactinaemia are conditions that might lead to infertility as a consequence. The aim of this article was to present the current knowledge about possible relationships between prolactin/hyperprolactinaemia and endometriosis-related infertility. Experimental studies on local prolactin acting as cytokine and relationship of prolactin and endometriotic tissue, as well as clinical studies on hyperprolactinaemia and endometriosis-related infertility suggest the possible role of prolactin in endometriosis-related infertility, but final proof is still missing and the exact pathogenesis of infertility in such cases is still under investigation. Novel strategies in the treatment of endometriosis-related infertility, based on its connection with prolactin such as the use of prolactin receptor antibodies and prolactin receptor antagonists, are under investigation, but adequate clinical studies have yet to be undertaken.

The Role of Prolactin as a Disease Activity Indicator in Some Rheumatic Diseases

The Role of Prolactin as a Disease Activity Indicator in Some Rheumatic Diseases

The role of prolactin levels in metabolic syndrome: a systematic review

Introduction and purpose: Prolactin is primarily associated with lactation and gonadal function, but it also has metabolic effects. Recent research shows prolactin's role in food intake, body weight, glucose, and lipid profile. Both low and excessive prolactin levels can lead to metabolic dysfunctions such as metabolic syndrome, type 2 DM, and dyslipidemia. Dopamine agonists, like cabergoline, used to treat hyperprolactinemia, may help balance metabolic homeostasis, likely due to their effect on prolactin. This study aims to synthesize current research on prolactin's metabolic effects, focusing on metabolic syndrome.State of knowledge: Metabolic syndrome is a cluster of dysfunctions like central obesity, atherogenic dyslipidemia, hypertension, and insulin resistance. It increases the risk of diabetes and cardiovascular diseases, affecting a quarter of the European population. Different combinations of metabolic syndrome components require various treatment approaches. New research focuses on prolactin and dopamine agonists in its pathogenesis and treatment.Materials and methods: This literature review is based on PubMed materials using keywords “prolactin,” “hyperprolactinemia,” “hypoprolactinemia,” “metabolic syndrome,” “diabetes mellitus,” “obesity.”Conclusions: This study highlights prolactin's importance in metabolic homeostasis, finding a positive correlation between both low and high prolactin levels and metabolic syndrome. However, gender differences and the pathogenesis of metabolic disorders should be further explored.

The Role of Prolactin in Amniotic Membrane Regeneration: Therapeutic Potential for Premature Rupture of Membranes.

Premature rupture of membranes (PROM) is defined as rupture of fetal membranes before the onset of labor. Prolactin (PRL) is secreted by decidual membranes and accumulated significantly in the amniotic fluid during pregnancy. PRL could ameliorate inflammation and collagen degradation in fetal membranes. However, the role of PRL in amniotic membrane is not well characterized. We isolated human amniotic epithelial stem cells (hAESCs) from human fetal membranes to study the effect of PRL on proliferation, migration, and antioxidative stress. Amniotic pore culture technique (APCT) model was constructed to evaluate the tissue regeneration effect in vitro. The potential targets and pathways of PRL acting in amnion via integrated bioinformatic methods. PRL had a dose-dependent effect on hAESCs in vitro. PRL (500 ng/mL) significantly improved the viability of hAESCs and inhibited cell apoptosis, related to the upregulation of CCN2 expression and downregulation of Bax, Caspase 3, and Caspase 8. PRL accelerated migration process in hAESCs via downregulation of MMP2, MMP3, and MMP9. PRL attenuated the cellular damage and mitochondrial dysfunction induced by hydrogen peroxide in hAESCs. PRL accelerated the healing process in the APCT model significantly. The top 10 specific targets (IGF1R, SIRT1, MAP2K1, CASP8, MAPK14, MCL1, NFKB1, HIF1A, MTOR, and HSP90AA1) and signaling pathways (such as HIF signaling pathway) were selected using an integrated bioinformatics approach. PRL improves the viability and antioxidative stress function of hAESCs and the regeneration of ruptured amniotic membranes in vitro. Thus, PRL has great therapeutic potential for prevention and treatment of ruptured membranes.

Role of prolactin in the protective effect of amisulpride against 1,2-Diacetylbenzene’s neurotoxicity

Exposure to organic solvents is associated with various health problems, including neurodegenerative diseases. Among these solvents, 1,2-diethylbenzene is notable for its ability to produce a toxic metabolite, 1,2-Diacetylbenzene (DAB), which can cause memory impairment. Prolactin (PRL) is theorized to protect the central nervous system. Certain antipsychotic drugs, known for increasing PRL secretion, have shown to improve cognitive performance in psychotic Alzheimer's patients. Among these, amisulpride stands out for its high efficacy, limited side effects, and high selectivity for dopamine D2 receptors. In our study, we explored the potential of amisulpride to inhibit DAB-induced neurotoxicity via PRL activation. Our results show that amisulpride enhances the PRL/JAK/STAT, PI3K/AKT, and BDNF/ERK/CREB pathways, playing critical roles in PRL’s neuroprotection pathways and memory formation. Additionally, amisulpride inhibited DAB-triggered NLRP3 inflammasome activation and apoptosis. Collectively, these findings suggest that amisulpride may be a promising therapeutic intervention for DAB-induced neurotoxicity, partly through activating the PRL pathway.

Prolactin effects on the pathogenesis of diabetes mellitus.

Prolactin (PRL) is a pituitary hormone promoting lactation in response to the suckling reflex. Beyond its well-known effects, novel tissue-specific and metabolic functions of PRL are emerging. To dissect PRL as a critical mediator of whole-body gluco-insulinemic sensitivity. PubMed-based search with the following terms 'prolactin', 'glucose metabolism', 'type 2 diabetes mellitus', 'type 1 diabetes mellitus', 'gestational diabetes mellitus' was performed. The identification of the PRL-glucose metabolism network poses the basis for unprecedented avenues of research in the pathogenesis of diabetes mellitus type 1 or 2, as well as of gestational diabetes. In this regard, it is of timely relevance to define properly the homeostatic PRL serum levels since glucose metabolism could be influenced by the circulating amount of the hormone. This review underscores the basic mechanisms of regulation of pancreatic β-cell functions by PRL and provides a revision of articles which have investigated the connection between PRL unbalancing and diabetes mellitus. Future studies are needed to elucidate the burden and the role of PRL in the regulation of glucose metabolism and determine the specific PRL threshold that may impact the management of diabetes. A careful evaluation and context-driven interpretation of PRL levels (e.g., pregnancy, PRL-secreting pituitary adenomas, drug-related hyper- and hypoprolactinemia) could be critical for the correct screening and management of glucometabolic disorders, such as type 1 or 2 as well as gestational diabetes mellitus.

Serum prolactin levels were positively related to metabolic indexes and disorders in male obese patients.

The role of prolactin (PRL) in glucolipid metabolism was inconsistent, and there were few studies on the metabolic role of PRL in obese patients. The study aims to explore association between PRL level and metabolic disorders in male obese patients. A retrospective study was conducted. Eighty-nine male patients with obesity were included, and their clinical data were recorded. A total of 89 male obese patients were included in this study. Their average age was 24.5 ± 9.0 years and BMI was 42.8 ± 9.1 kg/m2. The average waist circumference and body fat percentage was 129.6 ± 19.6 cm and 42.9 ± 8.0%, respectively. The median prolactin levels were 10.0 ng/ml (range: 3.93-30.1 ng/ml). 79.0% (49/62) of these patients presented with NAFLD and 77.3% (68/88) of them was dyslipidemia. Further, serum prolactin level was positively correlated with BMI (r = 0.225, P = 0.034), body fat percentage (r = 0.326, P = 0.017), ALT (r = 0.273, P = 0.011) and AST (r = 0.245, P = 0.029). Compared with low PRL group (<10 ng/ml), the incidence of morbid obesity and NAFLD was higher in high PRL group (morbid obesity: 71.1% vs 45.5%, P = 0.018 and NAFLD: 91.2% vs 64.3%, P = 0.013). In addition, the risk of NAFLD and morbid obesity in high PRL group (>10 ng/ml) was higher than low PRL group (OR:5.187, 95%CI 1.194-22.544, P = 0.028 and OR: 4.375, 95% CI 1.595-11.994, P = 0.004). The increased risk of NAFLD and morbid obesity in the high PRL group still existed after adjusting for age and Testosterone. Serum prolactin levels were positively associated with deterioration of metabolic indexes in male obese patients, as well as NAFLD and morbid obesity.

Current Insights in Prolactin Signaling and Ovulatory Function.

Prolactin (PRL) is a pleiotropic hormone released from lactotrophic cells of the anterior pituitary gland that also originates from extrapituitary sources and plays an important role in regulating lactation in mammals, as well as other actions. Acting in an endocrine and paracrine/autocrine manner, PRL regulates the hypothalamic-pituitary-ovarian axis, thus influencing the maturation of ovarian follicles and ovulation. This review provides a detailed discussion of the current knowledge on the role of PRL in the context of ovulation and ovulatory disorders, particularly with regard to hyperprolactinemia, which is one of the most common causes of infertility in women. Much attention has been given to the PRL structure and the PRL receptor (PRLR), as well as the diverse functions of PRLR signaling under normal and pathological conditions. The hormonal regulation of the menstrual cycle in connection with folliculogenesis and ovulation, as well as the current classifications of ovulation disorders, are also described. Finally, the state of knowledge regarding the importance of TIDA (tuberoinfundibular dopamine), KNDγ (kisspeptin/neurokinin B/dynorphin), and GnRH (gonadotropin-releasing hormone) neurons in PRL- and kisspeptin (KP)-dependent regulation of the hypothalamic-pituitary-gonadal (HPG) axis in women is reviewed. Based on this review, a rationale for influencing PRL signaling pathways in therapeutic activities accompanying ovulation disorders is presented.

The role of prolactin in the suppression of the response to restraint stress in the lactating mouse.

Suppression of the hypothalamic-pituitary-adrenal (HPA) axis is a well-characterised maternal adaptation that limits the exposure of the offspring to maternally-derived stress hormones. This current study has investigated the possible involvement of the lactogenic hormone, prolactin, in this physiologically important adaptation. As expected, circulating prolactin levels were higher in unstressed lactating mice compared to their virgin counterparts. Interestingly however, the ability of an acute period of restraint stress to further elevate prolactin levels was diminished in the former group. The stress-induced rise in prolactin levels in the virgin animals was concurrent with an increase in prolactin receptor activation within the adrenal cortical cells. This adrenal response was not seen in either the stressed or control lactation group, an observation that may be in part explained by the observed downregulation of prolactin receptor mRNA expression within this tissue. Further evidence of suppression of the HPA axis during lactation was revealed using in situ hybridisation to demonstrate that while acute restraint stress increased corticotrophin releasing hormone (CRH) mRNA expression in the hypothalamic paraventricular nucleus in both virgin and lactating mice, the magnitude of this response was reduced in the latter group. This potentially adaptive response did not, however, appear to result from the altered prolactin profile during lactation because it was not affected by the pharmacological suppression of prolactin secretion from the pituitary. This study therefore suggests that during lactation the response of the HPA axis to stress is suppressed at multiple physiological levels which are mediated by both prolactin-dependent and prolactin-independent mechanisms.

Hormonal and pheromonal studies on amphibians with special reference to metamorphosis and reproductive behavior.

In this article, we have reviewed studies which have been conducted to investigate the hormonal influence on metamorphosis in the bullfrog (Rana catesbeiana) and Japanese toad (Bufo japonicus) larvae, in addition to studies conducted on the hormonal and pheromonal control of reproductive behavior in red-bellied newts (Cynops pyrrhogaster). Metamorphosis was studied with an emphasis on the roles of prolactin (PRL) and thyrotropin (TSH). The release of PRL was shown to be regulated by thyrotropin-releasing hormone (TRH) and that of TSH was evidenced to be regulated by corticotropin-releasing factor. The significance of the fact that the neuropeptide that control the secretion of TSH is different from those encountered in mammals was discussed in consideration of the observation that the release of TRH, which stimulates the release of PRL, is enhanced when the animals are subjected to a cold temperature. Findings that were made by using melanin-rich cells of Bufo embryos and larvae, such as the determination of the origin of the adenohypophyseal primordium, identification of the pancreatic chitinase, and involvement of the rostral preoptic recess organ as the hypothalamic inhibitory center of α-melanocyte-stimulating hormone (α-MSH) secretion have been mentioned in this article. In addition, the involvement of hormones in eliciting the courtship behavior in the male red-bellied newts and discovery of the peptide sex pheromones and hormonal control of their secretion have also been included in the present article. This article is protected by copyright. All rights reserved.

(050) Low Prolactin Level Identifies Hypoactive Sexual Desire Disorder Women With a Reduced Inhibition Profile

Abstract Introduction Data on the role of prolactin (PRL) in the physiologic range in the female sexual response are scanty. Objective To investigate the association between PRL and sexual function as assessed by the Female Sexual Function Index (FSFI). We explored the presence of a cut-off level of PRL able to identify Hypoactive Sexual Desire Disorder (HSDD). Methods N=264 pre- and post-menopausal women consulting for FSD and sexually active were included in this observational, retrospective study. A clinical, biochemical and psychosexual evaluation was performed. Main Outcome measures: FSFI, Female Sexual Distress Scale-Revised, Middlesex Hospital Questionnaire and Sexual excitation/sexual inhibition scale (SIS/SES). HSDD was diagnosed through a clinical interview. Results In a multivariate model, PRL showed a significant, positive correlation with FSFI Desire (p=0.009) and Satisfaction (p=0.011). Women with PRL in the V quintile (14.58-24.59 μg/L) reported significantly higher FSFI Desire scores than those with PRL in the I quintile (5.12-6.53 μg/L). Women with HSDD presented a significantly lower PRL level than those without (p=0.032). A ROC curve analysis for PRL showed an accuracy of 0.610+-0.044 (p=0.014) in predicting HSDD. With a threshold of 9.83 μg/L, sensitivity and specificity for HSDD were 63% and 56%, respectively. Subjects with PRL =9.83 μg/L. The difference in SIS1 score was independent of cortisol. Conclusions Among FSD women with normo-PRL levels, those with the lowest levels demonstrated a poorer sexual desire than those with the highest levels. PRL &amp;lt;9.83 μg/L could predict HSDD and a lower sexual inhibitory trait. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: LV received scientific research grants, advisory board attendance and speaker honoraria from Therascience, Theramex, Bayer Schering Pharma, Intercept, Lipocine, Ibsa.

Low prolactin level identifies hypoactive sexual desire disorder women with a reduced inhibition profile

PurposeData on the role of prolactin (PRL) in the physiologic range in the female sexual response are scanty. We aimed at investigating the association between PRL and sexual function as assessed by the Female Sexual Function Index (FSFI). We explored the presence of a cut-off level of PRL able to identify Hypoactive Sexual Desire Disorder (HSDD).Methods277 pre- and post-menopausal women consulting for Female Sexual Dysfunction (FSD) and sexually active were enrolled in an observational, retrospective study. 42 women were used as no-FSD controls. A clinical, biochemical and psychosexual evaluation was performed. The main outcome measures were: FSFI, Female Sexual Distress Scale-Revised, Middlesex Hospital Questionnaire and Sexual excitation/sexual inhibition scale (SIS/SES).ResultsNormo-PRL FSD women (n = 264) showed lower FSFI Desire score than controls (n = 42), and higher than hyper-PRL FSD women (n = 13). These differences emerged both in pre-menopausal and post-menopausal subjects. In the normo-PRL FSD group, those with PRL in the higher quintile reported higher FSFI Desire scores than those with PRL in the lowest quintile. Women with HSDD presented a lower PRL level than those without (p = 0.032). A ROC curve analysis for PRL showed an accuracy of 0.610 ± 0.044 (p = 0.014) in predicting HSDD. With a threshold of < 9.83 μg/L, sensitivity and specificity for HSDD were 63% and 56%, respectively. Subjects with PRL < 9.83 μg/L also reported lower sexual inhibition (p = 0.006) and lower cortisol levels (p = 0.003) than those with PRL > = 9.83 μg/L.ConclusionsHyper-PRL is associated with low desire; however, among normo-PRL FSD women, those with the lowest levels demonstrated a poorer desire than those with the highest levels. PRL < 9.83 μg/L predicted HSDD and a lower sexual inhibitory trait.

The Involvement of Prolactin in Stress-Related Disorders.

The most important and widely studied role of prolactin (PRL) is its modulation of stress responses during pregnancy and lactation. PRL acts as a neuropeptide to support physiological reproductive responses. The effects of PRL on the nervous system contribute to a wide range of changes in the female brain during pregnancy and the inhibition of the hypothalamic-pituitary axis. All these changes contribute to the behavioral and physiological adaptations of a young mother to enable reproductive success. PRL-driven brain adaptations are also crucial for regulating maternal emotionality and well-being. Hyperprolactinemia (elevated PRL levels) is a natural and beneficial phenomenon during pregnancy and lactation. However, in other situations, it is often associated with serious endocrine disorders, such as ovulation suppression, which results in a lack of offspring. This introductory example shows how complex this hormone is. In this review, we focus on the different roles of PRL in the body and emphasize the results obtained from animal models of neuropsychiatric disorders.

Prolactin enzyme-linked immunosorbent assay for rhinoceroses – Another tool for assessing reproductive function and dysfunction in this taxon

For decades, progesterone and its metabolites have served as the primary biomarkers for monitoring reproductive activity in rhinoceroses, whereas protein hormones have received little attention despite their potential value in understanding reproductive function and dysfunction in this taxon. The goals of this study were to: 1) identify an enzyme-linked immunosorbent assay (ELISA) effective in measuring rhinoceros serum prolactin, 2) generate representative prolactin data in male and female rhinoceroses in diverse reproductive states, and 3) characterize prolactin throughout pregnancy in a white rhinoceros that exhibited mid-gestation lactation. Our results indicated that an equine prolactin ELISA by CUSABIO® is effective in measuring serum prolactin concentrations in white, black and Sumatran rhinoceroses. Preliminary data suggested that prolactin is lowest in males and acyclic females, but also appeared low during post-partum lactation. In contrast, prolactin concentrations were elevated in pregnant females and moderate in sexually mature females experiencing reproductive cyclicity. Prolactin increased following conception and generally continued to rise throughout pregnancy in the one pregnant white rhinoceros profiled herein. Spikes and dips in prolactin and progesterone, respectively, were documented around the time of mid-gestation mammary development and colostrum production in this individual and may provide some clues into the physiological triggers of this newly described aberrant reproductive condition. In conclusion, we have identified a new tool for studying reproductive activity in rhinoceroses, generated preliminary data, and revealed an intriguing relationship between prolactin fluctuations and premature lactation. This work provides the foundation for larger, focused studies on the role of prolactin in this taxon.

The relationship of circulating prolactin levels to the size of primary tumor in breast cancer patients

Background: Normal breast tissue cells are sensitive to the number of hormones among which estrogen and prolactin have the most dramatic effect on the breast. Malignant breast tissue cells can behave in this respect similar to the normal cells. Prolactin is necessary for maintenance and proliferation of ductal cells. Alteration in either the qualitative or quantitative expression of prolactin or in receptor could contribute to the pathogenesis of breast cancer. Aim and Objectives: The aim of the study was to evaluate serum prolactin level in pre-menopausal and post-menopausal breast cancer patient and to establish the correlation of circulating prolactin levels with parameters of primary tumor size and to evaluate the prolactin as a potential marker in histologically confirmed breast cancer patients. Materials and Methods: The present study was conducted in the department of general surgery and department of biochemistry on 40 female patients of histopathologically confirmed breast cancer referred by the department of general surgery, rajindra hospital patiala which were taken as study group, while 20 healthy females were taken as control group. Results: The comparison of serum prolactin levels of pre-operative versus post-operative 1 month shows P &lt; 0.0001 and t = 5.668 which is extremely significant. The comparison of serum prolactin levels of post-operative 1 month versus post-operative 6 months was found to be non-significant. The comparison of serum prolactin levels of preoperative versus post-operative 6 months showed P &lt; 0.0001 and t value-6.077 which was extremely significant. Conclusion: It is thus concluded that role of prolactin as an etiological factor in the initiation of the breast cancer in human has not been firmly documented. Furthermore, it still remains to be clarified whether hyper prolactinemia is the result or the cause of breast cancer.

Involvement of the PRL-PAK1 Pathway in Cancer Cell Migration.

Prolactin (PRL) is a polypeptide hormone synthesized in the lactotrophs of the adenohypophysis and in extrahypophyseal glands (such as the prostate and breasts) where it promotes their development. PRL is also involved in cancer development in these glands. It has been shown to stimulate cancer cell migration, suggesting its possible involvement in metastasis, in which cell migration plays an essential role. However, the role of PRL in cell migration is still unclear. Moreover, the intracellular mechanisms activated by PRL to carry out cell migration are less well understood. PRL exerts its effects via the PRL receptor (PRLR), which leads intracellularly to phosphorylation of Janus protein kinase 2 (JAK2), which in turn phosphorylates p21-activated protein kinase (PAK1), leading to an increase in cell migration. Although several studies have described the involvement of the PRL-PAK1 pathway in breast cancer cell migration, the molecular mechanisms have not been fully elucidated and there is no integration of these into signaling pathways. This study was conducted based on literature search of review articles and original research in the PubMed database, using the following keywords: PRL, cell migration, PRL and cell migration, PAK1 and signaling pathways. The aim of this review article was to describe the major signaling pathways controlled by PRL-PAK1 and propose a comprehensive model of the signaling pathways associated with PRL-PAK1.