In vitro regulation of gene expression of pregnancy-associated proteins and cytokines in bovine endometrial epithelial cells and bovine trophoblastic cells by infection with Neospora caninum

Abortion caused by the parasite Neospora caninum is an important threat to the livestock industry worldwide. Trophoblasts and caruncular cells play major roles in initiating innate immune responses and controlling parasite infection at the fetal-maternal interface. In the present study, bovine uterine epithelial cells (BUECs) and bovine trophoblastic (BT) cells treated with bovine interferon-gamma (IFN-γ), IFN-alpha (IFN-α) and IFN-tau (IFN-τ) followed by infection with N. caninum were examined by measuring the mRNA expression levels of numerous pregnancy-associated proteins and observing parasite growth to elucidate the host-parasite interaction at the uteroplacental region. N. caninum infection increased the expression of prolactin-related protein 1 (PRP1), pregnancy-associated glycoprotein 1 (PAG1), and cytokines (TNF-α, IL-8 and IL-10) in BUECs and of IL-8 in BT cells. Bovine IFN-γ inhibited IL-8 and TNF-α expression in BUECs and IL-8 in BT cells. In contrast, the expression of the interferon-stimulated gene OAS1 was significantly increased by treatment of the infected BT cells with IFN-γ. However, treatment with bovine IFNs did not inhibit N. caninum growth in either cell line. In conclusion, our results suggest that bovine IFN-γ plays a crucial role in control of pathogenesis in uterus and induction of inflammatory response in the placental region following N. caninum infection, rather than growth inhibition of the parasites.

Magnetogenetics as a promising tool for controlling cellular signaling pathways

Magnetogenetics emerges as a transformative approach for modulating cellular signaling pathways through the strategic application of magnetic fields and nanoparticles. This technique leverages the unique properties of magnetic nanoparticles (MNPs) to induce mechanical or thermal stimuli within cells, facilitating the activation of mechano- and thermosensitive proteins without the need for traditional ligand-receptor interactions. Unlike traditional modalities that often require invasive interventions and lack precision in targeting specific cellular functions, magnetogenetics offers a non-invasive alternative with the capacity for deep tissue penetration and the potential for targeting a broad spectrum of cellular processes. This review underscores magnetogenetics' broad applicability, from steering stem cell differentiation to manipulating neuronal activity and immune responses, highlighting its potential in regenerative medicine, neuroscience, and cancer therapy. Furthermore, the review explores the challenges and future directions of magnetogenetics, including the development of genetically programmed magnetic nanoparticles and the integration of magnetic field-sensitive cells for in vivo applications. Magnetogenetics stands at the forefront of cellular manipulation technologies, offering novel insights into cellular signaling and opening new avenues for therapeutic interventions.

Hyperprolactinemia modifies extracellular matrix components associated with collagen fibrillogenesis in harderian glands of non- and pregnant female mice

The harderian gland (HG) is a gland located at the base of the nictating membrane and fills the inferomedial aspect of the orbit in rodents. It is under the influence of the hypothalamic-pituitary-gonadal axis and, because of its hormone receptors, it is a target tissue for prolactin (PRL) and sex steroid hormones (estrogen and progesterone). In humans and murine, the anterior surface of the eyes is protected by a tear film synthesized by glands associated with the eye. In order to understand the endocrine changes caused by hyperprolactinemia in the glands responsible for the formation of the tear film, we used an animal model with metoclopramide-induced hyperprolactinemia (HPRL). Given the evidences that HPRL can lead to a process of cell death and tissue fibrosis, the protein expression of small leucine-rich proteoglycans (SLRPs) was analyzed through immunohistochemistry in the HG of the non- and the pregnant female mice with hyperprolactinemia. The SRLPs are related to collagen fibrillogenesis and they participate in pro-apoptotic signals. Our data revealed that high prolactin levels and changes in steroid hormones (estrogen and progesterone) can lead to an alteration in the amount of collagen, and in the structure of type I and III collagen fibers through changes in the amounts of lumican and decorin, which are responsible for collagen fibrillogenesis. This fact can lead to the impaired functioning of the HG by excessive apoptosis in the HG of the non- and the pregnant female mice with HPRL and especially in the HG of pregnancy-associated hyperprolactinemia.

Recent findings on hyperprolactinemia and its pathological implications: a literature review

The prolactin hormone (PRL) is often secreted by lactotrophic cells of the anterior pituitary and has been shown to play a role in various biological processes, including breast feeding and reproduction. The predominant form of this hormone is the 23 kDa form and acts through its receptor (PRLR) on the cell membrane. This receptor is a member of the superfamily of hematopoietic/cytokine receptors. PRL also has a 16 kDa subunit with anti-angiogenic, proapoptotic, and anti-inflammatory effects which is produced by the proteolytic breakdown of this hormone under oxidative stress. Although the common side effects of hyperprolactinemia are exerted on the reproductive system, new studies have shown that hyperprolactinemia has a wide variety of effects, including playing a role in the development of autoimmune diseases and increasing the risk of cardiovascular disease, peripartum cardiomyopathy, and diabetes among others. The range of PRL functions is increasing with the discovery of multiple sites of PRL secretion as well as PRLR expression in various tissues. This review summarizes current knowledge of the biology of PRL and its receptor, as well as the role of PRL in human pathophysiology.

The Influence of Ketone Bodies on Circadian Processes Regarding Appetite, Sleep and Hormone Release: A Systematic Review of the Literature

Chrononutrition is an emerging branch of chronobiology focusing on the profound interactions between biological rhythms and metabolism. This framework suggests that, just like all biological processes, even nutrition follows a circadian pattern. Recent findings elucidated the metabolic roles of circadian clocks in the regulation of both hormone release and the daily feeding–fasting cycle. Apart from serving as energy fuel, ketone bodies play pivotal roles as signaling mediators and drivers of gene transcription, promoting food anticipation and loss of appetite. Herein we provide a comprehensive review of the literature on the effects of the ketogenic diets on biological processes that follow circadian rhythms, among them appetite, sleep, and endocrine function.

Integrating machine learning with electronic health record data to facilitate detection of prolactin level and pharmacovigilance signals in olanzapine-treated patients

BACKGROUND AND AIM

Available evidence suggests elevated serum prolactin (PRL) levels in olanzapine (OLZ)-treated patients with schizophrenia. However, machine learning (ML)-based comprehensive evaluations of the influence of pathophysiological and pharmacological factors on PRL levels in OLZ-treated patients are rare. We aimed to forecast the PRL level in OLZ-treated patients and mine pharmacovigilance information on PRL-related adverse events by integrating ML and electronic health record (EHR) data.

METHODS

Data were extracted from an EHR system to construct an ML dataset in 672×384 matrix format after preprocessing, which was subsequently randomly divided into a derivation cohort for model development and a validation cohort for model validation (8:2). The eXtreme gradient boosting (XGBoost) algorithm was used to build the ML models, the importance of the features and predictive behaviors of which were illustrated by SHapley Additive exPlanations (SHAP)-based analyses. The sequential forward feature selection approach was used to generate the optimal feature subset. The co-administered drugs that might have influenced PRL levels during OLZ treatment as identified by SHAP analyses were then compared with evidence from disproportionality analyses by using OpenVigil FDA.

RESULTS

The 15 features that made the greatest contributions, as ranked by the mean (|SHAP value|), were identified as the optimal feature subset. The features were gender_male, co-administration of risperidone, age, co-administration of aripiprazole, concentration of aripiprazole, concentration of OLZ, progesterone, co-administration of sulpiride, creatine kinase, serum sodium, serum phosphorus, testosterone, platelet distribution width, α-L-fucosidase, and lipoprotein (a). The XGBoost model after feature selection delivered good performance on the validation cohort with a mean absolute error of 0.046, mean squared error of 0.0036, root-mean-squared error of 0.060, and mean relative error of 11%. Risperidone and aripiprazole exhibited the strongest associations with hyperprolactinemia and decreased blood PRL according to the disproportionality analyses, and both were identified as co-administered drugs that influenced PRL levels during OLZ treatment by SHAP analyses.

CONCLUSIONS

Multiple pathophysiological and pharmacological confounders influence PRL levels associated with effective treatment and PRL-related side-effects in OLZ-treated patients. Our study highlights the feasibility of integration of ML and EHR data to facilitate the detection of PRL levels and pharmacovigilance signals in OLZ-treated patients.

Minimal Effects of Cariprazine on Prolactin Levels in Bipolar Disorder and Schizophrenia

BACKGROUND

Many medications used to treat schizophrenia and bipolar I disorder are linked to hyperprolactinemia. The effects of cariprazine, a dopamine D₃/D₂ receptor partial agonist, on prolactin levels in patients with schizophrenia or bipolar I disorder were evaluated.

METHODS

Effects on prolactin were evaluated using pooled data from randomized, double-blind, placebo-controlled studies in patients with schizophrenia (4 studies; 6-week duration; cariprazine 1.5-3 mg/d, 4.5-6 mg/d, and 9-12 mg/d), bipolar mania (3 studies; 3-week duration; cariprazine 3-6 and 9-12 mg/d), and bipolar depression (3 studies; 6- to 8-week duration; cariprazine 1.5 and 3 mg/d). Long-term effects were analyzed using open-label studies in patients with schizophrenia (2 studies; 48-week duration) and patients with bipolar mania (1 study; 16-week duration). Change in prolactin levels (ng/mL) from baseline to study endpoint was evaluated in subsets of sex and prior medication use.

RESULTS

In patients with schizophrenia (male, n = 1377; female, n = 558), median prolactin changes were -1.2 for males and -7.4 for females on placebo, and ranged from -4.2 to -3.6 for males and -12.4 to +0.2 for females in the cariprazine-treatment groups. In patients with bipolar mania (male, n = 570; female, n = 395), median prolactin changes were -0.2 for males and -1.1 for females on placebo and ranged from -2.1 to -3.0 for males and 0 to +1.8 for females in the cariprazine-treatment groups. Median decreases were also seen in the long-term studies of schizophrenia (range, -14.6 to -2.0) and bipolar mania (range, -0.8 to +1.9). In patients with bipolar depression (male, n = 485; female, n = 780), median prolactin changes were +0.3 for males and +0.7 for females on placebo and ranged from +0.4 to +0.5 for males and +3.0 to +3.1 for females in the cariprazine-treatment groups.

CONCLUSION

Treatment with cariprazine for schizophrenia or bipolar I disorder was associated with minimal effects on prolactin levels.

The association between prolactin concentration and aggression in female patients with schizophrenia

OBJECTIVES

This study assessed the association between serum prolactin (PRL) concentration and aggression in female patients with schizophrenia.

METHODS

Female patients with schizophrenia (N = 120) were diagnosed using SCID-5 based on the DSM-5 criteria. They were sampled at the University Psychiatric Hospital Vrapce during the period from March 2017 to March 2019. Aggression was evaluated using the Positive and Negative Syndrome Scale (PANSS), and Overt Aggression Scale (OAS). Patients were subdivided into aggressive and non-aggressive groups. PRL was determined in serum using electrochemiluminescence (ECLIA) method.

RESULTS

Aggressive patients with schizophrenia had significantly (p < 0.0001) increased PRL concentration compared to non-aggressive patients. Higher PRL concentration was significantly (p < 0.0001) associated with pronounced aggressive symptoms determined by the OAS scores. When patients were subdivided into those who were treated with risperidone, haloperidol, paliperidone, amisulpride, and a group that was not treated with these antipsychotics, aggressive patients in both groups had significantly higher PRL concentrations than non-aggressive patients. Higher antipsychotic dose was related to increased PRL concentration (p = 0.004).

CONCLUSIONS

Our findings suggest that higher PRL is significantly associated with aggression, irrespective of the antipsychotic medication, in female patients with schizophrenia.

No evidence for prolactin's involvement in the post-ejaculatory refractory period

In many species, ejaculation is followed by a state of decreased sexual activity, the post-ejaculatory refractory period. Several lines of evidence have suggested prolactin, a pituitary hormone released around the time of ejaculation in humans and other animals, to be a decisive player in the establishment of the refractory period. However, data supporting this hypothesis is controversial. We took advantage of two different strains of house mouse, a wild derived and a classical laboratory strain that differ substantially in their sexual performance, to investigate prolactin's involvement in sexual activity and the refractory period. First, we show that there is prolactin release during sexual behavior in male mice. Second, using a pharmacological approach, we show that acute manipulations of prolactin levels, either mimicking the natural release during sexual behavior or inhibiting its occurrence, do not affect sexual activity or shorten the refractory period, respectively. Therefore, we show compelling evidence refuting the idea that prolactin released during copulation is involved in the establishment of the refractory period, a long-standing hypothesis in the field of behavioral endocrinology.

Safety and Efficacy of High-Dose Vitamin B6 as an Adjunctive Treatment for Antipsychotic-Induced Hyperprolactinemia in Male Patients With Treatment-Resistant Schizophrenia

This study aimed to investigate the safety and efficacy of high-dose vitamin B6 (vB6) as an adjunct treatment for antipsychotic-induced hyperprolactinemia (AIHP) in male patients with treatment-resistant schizophrenia (TRS). In this randomized double-blinded controlled study, patients were randomized (1:1) into a control group given aripiprazole (ARI; 10 mg/day; n = 100) or an intervention group given vB6 (300 mg/12 h for 16 weeks; n = 100). Prolactin levels, psychotic symptoms [Positive and Negative Syndrome Scale (PANSS)], cognitive function [MATRICS Consensus Cognitive Battery (MCCB)], liver function, kidney function, growth hormone level, micronutrient levels, blood lipids, and adverse secondary effects (ASEs)[Treatment Emergent Symptom Scale (TESS) and Barnes-Akathisia scale] were monitored. After a 16-week treatment period, the vB6 group showed a 68.1% reduction in serum prolactin levels (from 95.52 ± 6.30 μg/L to 30.43 ± 18.65 μg/L) while the ARI group showed only a 37.4% reduction (from 89.07 ± 3.59 μg/L to 55.78 ± 7.39 μg/L). During weeks 1-4, both treatments reduced prolactin similarly. Subsequently, the ARI effect plateaued, while the vB6 effect remained robust. The vB6 group showed better alleviation of psychotic symptoms and cognitive impairment. No serious ASEs were observed; ASEs were more frequent in the ARI group. AIHP reduction efficacy of vB6 was associated with baseline prolactin and triglyceride levels, total vB6 dosage, and education level. In conclusion, compared with the ARI group, TRS patients given vB6 showed better attenuation of AIHP, lower ASE scores, and greater improvements in clinical symptoms and cognitive impairments. These results support further consideration of vB6 as a putative treatment for AIHP. Trial Registration: ChiCTR1800014755.

Dynamic Regulation of JAK-STAT Signaling Through the Prolactin Receptor Predicted by Computational Modeling

Introduction

The expansion of insulin-producing beta cells during pregnancy is critical to maintain glucose homeostasis in the face of increasing insulin resistance. Prolactin receptor (PRLR) signaling is one of the primary mediators of beta cell expansion during pregnancy, and loss of PRLR signaling results in reduced beta cell mass and gestational diabetes. Harnessing the proliferative potential of prolactin signaling to expand beta cell mass outside of the context of pregnancy requires quantitative understanding of the signaling at the molecular level.

Methods

A mechanistic computational model was constructed to describe prolactin-mediated JAK-STAT signaling in pancreatic beta cells. The effect of different regulatory modules was explored through ensemble modeling. A Bayesian approach for likelihood estimation was used to fit the model to experimental data from the literature.

Results

Including receptor upregulation, with either inhibition by SOCS proteins, receptor internalization, or both, allowed the model to match experimental results for INS-1 cells treated with prolactin. The model predicts that faster dimerization and nuclear import rates of STAT5B compared to STAT5A can explain the higher STAT5B nuclear translocation. The model was used to predict the dose response of STAT5B translocation in rat primary beta cells treated with prolactin and reveal possible strategies to modulate STAT5 signaling.

Conclusions

JAK-STAT signaling must be tightly controlled to obtain the biphasic response in STAT5 activation seen experimentally. Receptor up-regulation, combined with SOCS inhibition, receptor internalization, or both is required to match experimental data. Modulating reactions upstream in the signaling can enhance STAT5 activation to increase beta cell survival.

Electronic supplementary material

The online version of this article (10.1007/s12195-020-00647-8) contains supplementary material, which is available to authorized users.

An Emerging Role for Prolactin in Female-Selective Pain

Women experience many pain conditions more frequently when compared with men, but the biological mechanisms underlying sex differences in pain remain poorly understood. In particular, little is known about possible sex differences in peripheral nociceptors, the fundamental building blocks of pain transmission. Emerging evidence reveals that prolactin (PRL) signaling at its cognate prolactin receptor (PRLR) in primary afferents promotes nociceptor sensitization and pain in a female-selective fashion. In this review, we summarize recent progress in understanding the female-selective role of PRL/PRLR in nociceptor sensitization and in pathological pain conditions, including postoperative, inflammatory, neuropathic, and migraine pain, as well as opioid-induced hyperalgesia. The clinical implications of the peripheral PRL/PRLR system for the discovery of new therapies for pain control in women are also discussed.

Adipose Stromal Cell Expansion and Exhaustion: Mechanisms and Consequences

Adipose tissue (AT) is comprised of a diverse number of cell types, including adipocytes, stromal cells, endothelial cells, and infiltrating leukocytes. Adipose stromal cells (ASCs) are a mixed population containing adipose progenitor cells (APCs) as well as fibro-inflammatory precursors and cells supporting the vasculature. There is growing evidence that the ability of ASCs to renew and undergo adipogenesis into new, healthy adipocytes is a hallmark of healthy fat, preventing disease-inducing adipocyte hypertrophy and the spillover of lipids into other organs, such as the liver and muscles. However, there is building evidence indicating that the ability for ASCs to self-renew is not infinite. With rates of ASC proliferation and adipogenesis tightly controlled by diet and the circadian clock, the capacity to maintain healthy AT via the generation of new, healthy adipocytes appears to be tightly regulated. Here, we review the contributions of ASCs to the maintenance of distinct adipocyte pools as well as pathogenic fibroblasts in cancer and fibrosis. We also discuss aging and diet-induced obesity as factors that might lead to ASC senescence, and the consequences for metabolic health.

Neuromedin U suppresses prolactin secretion via dopamine neurons of the arcuate nucleus

Neuromedin U (NMU) has a precursor that contains one additional peptide consisting of 33 or 36 amino acid residues. Recently, we identified this second peptide from rat brain and designated it neuromedin U precursor-related peptide (NURP), showing it to stimulate prolactin release from the pituitary when injected via the intracerebroventricular (icv) route. Here, we examined whether NMU, like NURP, also stimulates prolactin release. Unlike NURP, icv injection of NMU significantly decreased the secretion of prolactin from the pituitary. This suppression of prolactin release by NMU was observed in hyper-prolactin states such as lactation, stress, pseudopregnancy, domperidone (dopamine antagonist) administration, and icv injection of NURP. Immunohistochemical analysis revealed that icv injection of NMU induced cFos expression in dopaminergic neurons of the arcuate nucleus, but not the substantia nigra. Mice with double knockout of NMU and neuromedin S (NMS), the latter also binding to NMU receptors, showed a significant increase of the plasma prolactin level after domperidone treatment relative to wild-type mice. These results suggest that NMU and NURP may play important reciprocal roles in physiological prolactin secretion.

Effectiveness of absorption and passage through the small intestine, as a model of oral prolactin administration

The process of absorption and permeation of PRL through the small intestine of 1-day-old piglet from the different compositions of solutions prepared for oral administration was investigated. This was achieved by determining the effect of hormone concentration (0.25 mg / ml or 0.5 mg / ml or 0.75 mg / ml), the concentration of stabilizing substances - trehalose (6 mg / ml or 12 mg / ml or 18 mg / ml) and mannitol (6 mg / ml or 12 mg / ml or 18 mg / ml) and the pH of the solution (2.5 or 3.0 or 3.5) on the degree of absorption and permeation of the PRL. The conditions for the absorption and penetration of PRL from solutions of various compositions for oral administration through the natural membrane (small intestine of the 1-day-old sucking piglet) in the in vivo conditions were simulated. The studies used an in vivo model in which the enzymatic profile in the body is not yet fully developed (no pepsin). It was found that in the studied range the absorption of PRL in the small intestine of the 1-day-old sucking piglet is significantly related to the concentration of the hormone and trehalose in the solution from which it is absorbed. In contrast, all factors studied (hormone concentration, trehalose and mannitol concentration, pH value of the solution) influence the process of penetration of the PRL in the studied range. It was also found that the hormone concentration significantly influences the rate of its absorption and permeation (the fastest occurs at a concentration of 0.5 mg/mL). The results suggest possibility of oral prolactin administration in order to ensure proper growth, development and increase the resistance and survival of sucking piglets.

Rapid prolactin induction in adult male rats after treatment with diethylstilbestrol

Diethylstilbestrol (DES) is a synthetic oestrogen known to disrupt the endocrine system and to cause reproductive toxicity mediated via the hypothalamic-pituitary-adrenal axis; however, its molecular mechanism of action is poorly understood. In the present study, we found that, after only 1 week of exposure to DES, blood testosterone dramatically decreased and that this decrease was associated with a strong induction of prolactin (PRL). Even with the increase in PRL, the luteinising hormone and follicle-stimulating hormone mRNAs slightly decreased. Our results show that, after 48 hours of a single dose of DES, there was a six-fold increase in PRL expression. After exploring the upstream mechanisms, we determined that dopamine, which inhibits PRL secretion in male rats, did not decrease in the pituitary gland of DES-treated rats, whereas vasoactive intestinal peptide (VIP), which mediates the acute release of PRL, was elevated. Serotonin (5-HT) increased in the brain of male rats 24 hours after a single DES treatment; however, PRL, VIP or 5-HT was not induced by DES in female rats. Our results indicate that DES induces the expression of pituitary PRL in male rats by stimulating VIP in the hypothalamus and 5-HT in the central nervous system.

Changes in prolactin, cortisol and testosterone concentrations during queen succession in a colony of naked mole-rats (Heterocephalus glaber): a case study

Colonies of naked mole-rats (Heterocephalus glaber, NMRs) are characterised by an extreme skew in lifetime reproductive success with only one female and one to three male consorts in a colony. The rest of the individuals in a colony are reproductively suppressed and much research has been focussed on elucidating that mechanism. The dopamine system and prolactin have recently been implicated in the suppression of reproduction of subordinate NMRs. To investigate the changes in prolactin during the removal of an aged reproductive female (queen) and succession of a new queen, blood samples were collected during different stages of queen removal: before queen removal, after separation, but in olfactory contact with the queen and after the total removal of the queen. Further, plasma cortisol and testosterone concentrations were determined. The colony appeared unstable prior to queen removal as indicated by high concentrations of cortisol and testosterone and lack of successful breeding. A new queen succeeded the old queen whilst she was still in olfactory contact. The time preceding queen succession was characterised by high levels of aggression, the death of a number of individuals, high cortisol and testosterone and low prolactin concentrations. Once the older queen was removed entirely and the new queen had given birth, prolactin concentrations increased and cortisol and testosterone concentrations decreased in subordinate NMRs. The results suggest that low prolactin levels are associated with low reproductive suppression during times of colony instability due to the removal or death of a queen.

Impact of sulfur-containing amino acids on the plasma metabolomics and intestinal microflora of the sow in late pregnancy

Which optimum ratio of Met/Cys is better to maintain the health status of the sow during late pregnancy?

Suppression of Prolactin Secretion Partially Explains the Antidiabetic Effect of Bromocriptine in ob/ob Mice

Previous studies have shown that bromocriptine mesylate (Bromo) lowers blood glucose levels in adults with type 2 diabetes mellitus; however, the mechanism of action of the antidiabetic effects of Bromo is unclear. As a dopamine receptor agonist, Bromo can alter brain dopamine activity affecting glucose control, but it also suppresses prolactin (Prl) secretion, and Prl levels modulate glucose homeostasis. Thus, the objective of the current study was to investigate whether Bromo improves insulin sensitivity via inhibition of Prl secretion. Male and female ob/ob animals (a mouse model of obesity and insulin resistance) were treated with Bromo and/or Prl. Bromo-treated ob/ob mice exhibited lower serum Prl concentration, improved glucose and insulin tolerance, and increased insulin sensitivity in the liver and skeletal muscle compared with vehicle-treated mice. Prl replacement in Bromo-treated mice normalized serum Prl concentration without inducing hyperprolactinemia. Importantly, Prl replacement partially reversed the improvements in glucose homeostasis caused by Bromo treatment. The effects of the Prl receptor antagonist G129R-hPrl on glucose homeostasis were also investigated. We found that central G129R-hPrl infusion increased insulin tolerance of male ob/ob mice. In summary, our findings indicate that part of Bromo effects on glucose homeostasis are associated with decrease in serum Prl levels. Because G129R-hPrl treatment also improved the insulin sensitivity of ob/ob mice, pharmacological compounds that inhibit Prl signaling may represent a promising therapeutic approach to control blood glucose levels in individuals with insulin resistance.

Antipsychotic-induced hyperprolactinaemia: case studies and review

Antipsychotics are a known cause of hyperprolactinaemia and can be associated with significant health issues in short term and long term. The effects vary with gender and age of the individual and can contribute towards non-concordance and hence relapse in mental health of our patients. Clinicians need to educate the patients about this significant side effect of not only antipsychotic medications but other medications causing hyperprolactinaemia commonly prescribed in primary care.

Understanding the Inguinal Sinus in Sheep (Ovis aries)-Morphology, Secretion, and Expression of Progesterone, Estrogens, and Prolactin Receptors

Post-parturient behavior of mammalian females is essential for early parent–offspring contact. After delivery, lambs need to ingest colostrum for obtaining the related immunological protection, and early interactions between the mother and the lamb are crucial. Despite visual and auditory cues, olfactory cues are decisive in lamb orientation to the mammary gland. In sheep, the inguinal sinus is located bilaterally near the mammary gland as a skin pouch (IGS) that presents a gland that secretes a strong-smelling wax. Sheep IGS gland functions have many aspects under evaluation. The objective of the present study was to evaluate sheep IGS gland functional aspects and mRNA transcription and the protein expression of several hormone receptors, such as progesterone receptor (PGR), estrogen receptor 1 (ESR1), and 2 (ESR2) and prolactin receptor (PRLR) present. In addition, another aim was to achieve information about IGS ultrastructure and chemical compounds produced in this gland. All hormone receptors evaluated show expression in IGS during the estrous cycle (follicular/luteal phases), pregnancy, and the post-partum period. IGS secretion is rich in triterpenoids that totally differ from the surrounding skin. They might be essential substances for the development of an olfactory preference of newborns to their mothers.

Neuroendocrine control in social relationships in non-human primates: Field based evidence

Primates maintain a variety of social relationships and these can have fitness consequences. Research has established that different types of social relationships are unpinned by different or interacting hormonal systems, for example, the neuropeptide oxytocin influences social bonding, the steroid hormone testosterone influences dominance relationships, and paternal care is characterized by high oxytocin and low testosterone. Although the oxytocinergic system influences social bonding, it can support different types of social bonds in different species, whether pair bonds, parent-offspring bonds or friendships. It seems that selection processes shape social and mating systems and their interactions with neuroendocrine pathways. Within species, there are individual differences in the development of the neuroendocrine system: the social environment individuals are exposed to during ontogeny alters their neuroendocrine and socio-cognitive development, and later, their social interactions as adults. Within individuals, neuroendocrine systems can also have short-term effects, impacting on social interactions, such as those during hunting, intergroup encounters or food sharing, or the likelihood of cooperating, winning or losing. To understand these highly dynamic processes, extending research beyond animals in laboratory settings to wild animals living within their natural social and ecological setting may bring insights that are otherwise unreachable. Field endocrinology with neuropeptides is still emerging. We review the current status of this research, informed by laboratory studies, and identify questions particularly suited to future field studies. We focus on primate social relationships, specifically social bonds (mother-offspring, father-offspring, cooperative breeders, pair bonds and adult platonic friendships), dominance, cooperation and in-group/out-group relationships, and examine evidence with respect to the 'tend and defend' hypothesis.

Prolactin Upregulates Female-Predominant P450 Gene Expressions and Downregulates Male-Predominant Gene Expressions in Mouse Liver

Prolactin is a polypeptide hormone with over 300 separate biologic activities. Its serum level is increased during pregnancy and lactation, and it has been reported that pregnancy and lactation affect drug and steroid metabolism in mice and humans. Several studies reported that pregnancy or lactation influences liver cytochrome P450 (P450) expression and its activity, affecting the biosynthesis of steroids and xenobiotics through growth hormone or sex hormones; however, the role of prolactin as the regulator of liver P450 expression has not been elucidated so far. In the present study, we focused on prolactin as the regulator of expression of liver sex-predominant genes, including P450s. To investigate the role of prolactin in the hepatic gene expressions, pCAGGS expression vector containing mouse prolactin cDNA was transfected by hydrodynamic injection into both male and female mice. Hyperprolactinemia phosphorylated signal transducer and activator of transcription 5 in the liver and augmented female mouse liver mRNA expression of Cyp3a16, Cyp3a41, Cyp3a44, Cyp2b9, and prolactin receptor genes, whose expressions were female-predominant in hepatocytes. Moreover, liver expression of male-predominant genes such as Cyp2d9, Cyp7b1, Mup1, and Alas2 were reduced in male mice with hyperprolactinemia. The serum levels of conventional regulators of hepatic gene expressions, growth hormone, and testosterone were not affected by hyperprolactinemia. We demonstrated that prolactin upregulated female-predominant genes in female mice and downregulated male-predominant genes in male mice. We conjecture that higher concentration of prolactin would alter steroid and xenobiotic metabolisms by modulating hepatic P450 gene expressions during pregnancy and lactation.

Sexual dysfunction in premenopausal women could be related to hormonal profile

Female sexual dysfunction (FSD) is a public health problem that affects women's quality of life. Although the relationship between some hormones and the FSD has been described, it is not well established for all hormones. Therefore, the aim of our study was to evaluate the association between hormonal dysfunction and sexual dysfunction in premenopausal women. We performed a cross-sectional study with 60 patients with regular menstrual cycles, with age ranging from 18 to 44 years, with previous diagnosis of FSD. All patients were evaluated using the female sexual function index (FSFI) questionnaire and had the levels of total testosterone, prolactin (PRL), thyroid-releasing hormone and free testosterone index measured. Among the 60 patients, 43 (71.7%) were diagnosed with hypoactive sexual desire disorder (HSDD), 9 (15%) had anorgasmy and 8 (3.3%) had sexual pain dysfunction. Hormonal evaluation, demonstrated that 79.1% of patients with HSDD, 78.4% of patients with anorgasmy and 50% of patients with sexual pain dysfunction had female androgen insensitivity. We can conclude that there is an important association between low levels of total and free testosterone and FSD. This finding offers a new alternative for diagnosis and treatment of HSDD. Moreover, given the potential role of androgens in sexual function, randomized controlled trials with adequate long-term follow-up are essential to confirm its possible effect.

Oestrogens, prolactin, hypothalamic-pituitary-gonadal axis, and schizophrenic psychoses

Interest is growing in the potential effect of gonadal hormones, prolactin, and the hypothalamic-pituitary-gonadal axis in schizophrenic psychoses. Many studies from clinical, epidemiological, and fundamental research have confirmed that oestradiol, the main component of oestrogens, can have protective effects in schizophrenic psychoses. Furthermore, many patients with schizophrenic psychoses-even in the untreated prodromal stages-have hyperprolactinaemia and gonadal dysfunction, with oestrogen deficiency in women and testosterone deficiency in men. The understanding of the pathogenetic mechanisms underlying these findings could contribute to a better understanding of the aetiopathogenesis of schizophrenic psychoses and improve therapeutic approaches. In this Series paper, we aim to review methodologically sound studies in this area, propose a theory to explain these findings in the context of psychosis, and suggest therapeutic strategies and implications for further research.

Influence of dynorphin on estradiol- and cervical stimulation-induced prolactin surges in ovariectomized rats

Prolactin is an anterior pituitary hormone necessary for fertility, pregnancy maintenance, lactation, and aspects of maternal behavior. In rodents, there is a surge of prolactin on the afternoon of proestrus, and a semi-circadian pattern of prolactin surges during early pregnancy, with a diurnal and nocturnal surge every day. Both of these patterns can be replicated in ovariectomized rats. A prior study demonstrated that central antagonism of κ-opioid receptors, the target of dynorphin, largely abolished the nocturnal prolactin surge in pregnant rats. We build on this to determine whether dynorphin, perhaps from the arcuate population that co-express kisspeptin, neurokinin B, and dynorphin (KNDy neurons), also contributes to the estradiol- or cervical stimulation-induced surges in ovariectomized rats. Ovariectomized rats were treated with either estradiol or cervical stimulation to induce prolactin surge(s). Blood samples were taken around the expected surge time to determine the effect of either acute κ-opioid receptor antagonism or previous chemical ablation of the KNDy population on prolactin levels. Dynorphin antagonism does significantly disrupt the nocturnal prolactin surge, but it does not contribute to the estradiol-induced surge. Chemical ablation of KNDy neurons had opposite effects; ablation of 40 % of the KNDy neurons had no impact on the nocturnal prolactin surge, while a somewhat larger ablation significantly reduced the size of the estradiol-induced surge. We conclude that dynorphin is likely a controlling factor for the nocturnal surge induced by cervical stimulation, and that other KNDy neuron products must play a role in the estradiol-induced surge.

Fertility and genomics: comparison of gene expression in contrasting reproductive tissues of female cattle

To compare gene expression among bovine tissues, large bovine RNA-seq datasets were used, comprising 280 samples from 10 different bovine tissues (uterine endometrium, granulosa cells, theca cells, cervix, embryos, leucocytes, liver, hypothalamus, pituitary, muscle) and generating 260 Gbases of data. Twin approaches were used: an information–theoretic analysis of the existing annotated transcriptome to identify the most tissue-specific genes and a de-novo transcriptome annotation to evaluate general features of the transcription landscape. Expression was detected for 97% of the Ensembl transcriptome with at least one read in one sample and between 28% and 66% at a level of 10 tags per million (TPM) or greater in individual tissues. Over 95% of genes exhibited some level of tissue-specific gene expression. This was mostly due to different levels of expression in different tissues rather than exclusive expression in a single tissue. Less than 1% of annotated genes exhibited a highly restricted tissue-specific expression profile and approximately 2% exhibited classic housekeeping profiles. In conclusion, it is the combined effects of the variable expression of large numbers of genes (73%–93% of the genome) and the specific expression of a small number of genes (<1% of the transcriptome) that contribute to determining the outcome of the function of individual tissues.

Chlorpromazine-Induced Hyperprolactinemia on Rat's Uterus

Background:

Hyperprolactinemia is a common side effect of antipsychotic drugs that requires further investigation. The current study was designed to evaluate dose-dependent effect of chlorpromazine (CPZ) on hormonal changes and uterine horn histological structure in rats. Moreover, the mammary glands were analyzed to show hyperprolactinemia-induced histological changes.

Methods:

Albino Wistar rats (n = 32) were divided into four groups. The first group was set as a control. In the three drug-treated groups (eight rats in each group), CPZ was administered by a gavage at doses of 3, 10, and 30 mg/kg/day for 28 days. One day after the last administration of the drug, the animals were sacrificed. Histopathological and histomorphometrical analyses of the uterine horns and mammary glands were carried out to evaluate dose-dependent effect of CPZ on histological structure. Serum levels of prolactin (PRL), estradiol, progesterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were also evaluated.

Results:

Remarkable (P < 0.05) elevation was observed in CPZ-administrated animals' uterine horn endometrium, myometrium, and perimetrium thicknesses, and the mammary glands were observed with galactorrhea features. The serum level of progesterone and PRL significantly (P < 0.05) increased, while the serum concentration of LH, FSH, and estradiol was notably (P < 0.05) decreased depending on administrated CPZ dose. No histological and biological changes were occurred in the control animals.

Conclusion:

The present findings suggest that CPZ-induced disturbances not only depend on PRL level and increased PRL level largely depends on administrated doses of the CPZ.

Variation in prolactin is related to variation in sexual behavior and contact affiliation

Prolactin is associated with both maternal and paternal care and appears important in developing a bond between parent and infant. In contrast with oxytocin, another hormone important in infant care, there is scant information on the role of prolactin in maintaining adult heterosexual relationships. We present here the first results demonstrating a relationship between prolactin levels and sexual and contact affiliation behavior in a pair-bonded species. We studied cotton-top tamarins, a socially-monogamous, cooperatively-breeding primate. We measured chronic urinary prolactin levels over a four week period to include the entire female ovulatory cycle and correlated prolactin levels in males and females with simultaneous measures of contact affiliation and sexual behavior. Current mothers who were no longer nursing displayed lower amounts of sexual behavior and proximity than non-breeding females and also had marginally lower levels of prolactin. The prolactin levels of males and females were similar within pairs, and variation in prolactin levels for both sexes was explained both by the amount of sexual behavior and contact affiliation. The results parallel a previous study that compared oxytocin levels with sociosexual behavior in the same species, and supports the hypothesis that both prolactin and oxytocin are involved in pair-bonding as well as in infant care.

Grass carp prolactin: molecular cloning, tissue expression, intrapituitary autoregulation by prolactin and paracrine regulation by growth hormone and luteinizing hormone

Prolactin (PRL), a pituitary hormone with diverse functions, is well-documented to be under the control of both hypothalamic and peripheral signals. Intrapituitary modulation of PRL expression via autocrine/paracrine mechanisms has also been reported, but similar information is still lacking in lower vertebrates. To shed light on autocrine/paracrine regulation of PRL in fish model, grass carp PRL was cloned and its expression in the carp pituitary has been confirmed. In grass carp pituitary cells, local secretion of PRL could suppress PRL release with concurrent rises in PRL production and mRNA levels. Paracrine stimulation by growth hormone (GH) was found to up- regulate PRL secretion, PRL production and PRL transcript expression, whereas the opposite was true for the local actions of luteinizing hormone (LH). Apparently, local interactions of PRL, GH and LH via autocrine/paracrine mechanisms could modify PRL production in carp pituitary cells through differential regulation of PRL mRNA stability and gene transcription.

Relationships among androgen receptor CAG repeat polymorphism, sex hormones and penile length in Han adult men from China: a cross-sectional study

This study aimed to investigate the correlations among androgen receptor (AR) CAG repeat polymorphism, sex hormones and penile length in healthy Chinese young adult men. Two hundred and fifty-three healthy men (aged 22.8 ± 3.1 years) were enrolled. The individuals were grouped as CAG short (CAG_S) if they harbored repeat length of ≤20 or as CAG long (CAG_L) if their CAG repeat length was >20. Body height/weight, penile length and other parameters were examined and recorded by the specified physicians; CAG repeat polymorphism was determined by the polymerase chain reaction (PCR) method; and the serum levels of the sex hormones were detected by radioimmunoassay. Student's t-test or linear regression analysis was used to assess the associations among AR CAG repeat polymorphism, sex hormones and penile length. This investigation showed that the serum total testosterone (T) level was positively associated with the AR CAG repeat length (P = 0.01); whereas, no significant correlation of T or AR CAG repeat polymorphism with the penile length was found (P = 0.593). Interestingly, an inverse association was observed between serum prolactin (PRL) levels and penile length by linear regression analyses (β= −0.024, P = 0.039, 95% confidence interval (CI): −0.047, 0). Collectively, this study provides the first evidence that serum PRL, but not T or AR CAG repeat polymorphism, is correlated with penile length in the Han adult population from northwestern China.

The role of oxytocin in male and female reproductive behavior

Oxytocin (OT) is a nonapeptide with an impressive variety of physiological functions. Among them, the 'prosocial' effects have been discussed in several recent reviews, but the direct effects on male and female sexual behavior did receive much less attention so far. As our contribution to honor the lifelong interest of Berend Olivier in the control mechanisms of sexual behavior, we decided to explore the role of OT in the present review. In the successive sections, some physiological mechanisms and the 'pair-bonding' effects of OT will be discussed, followed by sections about desire, female appetitive and copulatory behavior, including lordosis and orgasm. At the male side, the effects on erection and ejaculation are reviewed, followed by a section about 'premature ejaculation' and a possible role of OT in its treatment. In addition to OT, serotonin receives some attention as one of the main mechanisms controlling the effects of OT. In the succeeding sections, the importance of OT for 'the fruits of labor' is discussed, as it plays an important role in both maternal and paternal behavior. Finally, we pay attention to an intriguing brain area, the ventrolateral part of the ventromedial hypothalamic nucleus (VMHvl), apparently functioning in both sexual and aggressive behavior, which are at first view completely opposite behavioral systems.

Increased serum prolactin levels in drug-naive first-episode male patients with schizophrenia

BACKGROUND

Prolactin is a hormone receiving considerable attention in psychiatry. Increased serum prolactin level is frequently associated with dopamine blocking antipsychotics. Furthermore, decreased prolactin level was considered a reflector of the effect of antipsychotics. However, there is restricted numbers of investigations that researched baseline prolactin levels in first-episode patients with schizophrenia.

AIMS

We purpose to investigate serum baseline prolactin levels in drug-naive first-episode patients with schizophrenia (FES) and to explore the differences in serum prolactin levels between FES, drug-free schizophrenic patients (DFS) and healthy controls (HC).

MATERIAL AND METHODS

The study was conducted in the Departments of Psychiatry, Gölbaşı Hasvak and Kırklareli State Hospitals, Turkey. Thirty male FES, 41 male DFS and 32 male HC were included in study. All participants were clinically examined and individually interviewed. Before initiating any pharmacological treatment, 5 ml of venous blood was collected to measure serum prolactin levels between 08:00 and 10:00 h, which was determined by radioimmunoassay (RIA). Prolactin levels were also collected from the consenting HC using the same assay.

RESULTS

The mean age was higher in the DFS group. The mean score of Brief Psychiatric Rating Scale was higher in the FES group and mean score of Scale for the Assessment of Negative Symptoms was higher in the DFS group. The mean value of prolactin was higher in the FES group (34.1 ± 19.9 ng/dl) compared with DFS (17.9 ± 6.5 ng/dl) and HC (9.7 ± 2.3 ng/dl) (F = 35.5, P < 0.001). Additionally, the mean value of serum prolactin is higher in the DFS group compared with HC (P < 0.001).

CONCLUSION

To our knowledge, this study is the first to demonstrate higher serum prolactin levels in male FES compared with male DFS and male HC. Prolactin might act as a protective factor while first episode of schizophrenia is experienced. Future studies are needed to provide the role of prolactin in schizophrenia.

Missing and Possible Link between Neuroendocrine Factors, Neuropsychiatric Disorders, and Microglia

Endocrine systems have long been suggested to be one of the important factors in neuropsychiatric disorders, while the underlying mechanisms have not been well understood. Traditionally, neuropsychiatric disorders have been mainly considered the consequence of abnormal conditions in neural circuitry. Beyond the neuronal doctrine, microglia, one of the glial cells with inflammatory/immunological functions in the central nervous system (CNS), have recently been suggested to play important roles in neuropsychiatric disorders. However, the crosstalk between neuroendocrine factors, neuropsychiatric disorders, and microglia has been unsolved. Therefore, we herein introduce and discuss a missing and possible link between these three factors; especially highlighting the following hormones; (1) Hypothalamic-Pituitary-Adrenal (HPA) axis-related hormones such as corticotropin-releasing hormone (CRH) and glucocorticoids, (2) sex-related hormones such as estrogen and progesterone, and (3) oxytocin. A growing body of evidence has suggested that these hormones have a direct effect on microglia. We hypothesize that hormone-induced microglial activation and the following microglia-derived mediators may lead to maladaptive neuronal networks including synaptic dysfunctions, causing neuropsychiatric disorders. Future investigations to clarify the correlation between neuroendocrine factors and microglia may contribute to a novel understanding of the pathophysiology of neuropsychiatric disorders.

Prolactin expression in the cochlea of aged BALB/c mice is gender biased and correlates to loss of bone mineral density and hearing loss

Prolactin is a versatile hormone with over 300 known functions and predominantly expressed in the pituitary. However, its expression has additionally been found in a number of extrapituitary organs. Recently, we described the expression of prolactin in the inner ear of mice, where it was correlated to age. Previous research has shown prolactin to be linked to abnormal bone metabolism and hearing loss due to changes in morphology of the bony otic capsule. Here we further investigated the relationship between prolactin, hearing loss and cochlea bone metabolism. BALB/c mice were tested for hearing using ABR at 6 and 12 months of age. Bone mineral density of the cochlea was evaluated using microCT scanning. Prolactin expression was calculated using quantitative real time PCR. Expression of the key regulators of bone metabolism, osteoprotegerin and receptor activator of nuclear factor-kappaB ligand were also determined. We found that prolactin expression was exclusive to the female mice. This also correlated to a greater threshold shift in hearing for the females between 6 and 12 months of age. Analyses of the cochlea also show that the bone mineral density was lower in females compared to males. However, no gender differences in expression of osteoprotegerin or receptor activator of nuclear factor-kappaB ligand could be found. Further analysis of cochlea histological sections revealed larger ostocyte lacunae in the females. These results provide a possible mechanism for an age related hearing loss sub-type that is associated with gender and provides clues as to how this gender bias in hearing loss develops. In addition, it has the potential to lead to treatment for this specific type of hearing loss.

Female orgasm but not male ejaculation activates the pituitary. A PET-neuro-imaging study

The pituitary gland plays an important role in basic survival mechanisms by releasing fluctuating amounts of hormones into the bloodstream, depending on the circumstances the individual finds itself. However, despite these changes in pituitary hormonal production, neuroimaging studies have never been able to demonstrate changes in the activation level of the pituitary. The most apparent reason is the much higher blood flow rate in the pituitary than in the brain. However, the present PET-scanning study demonstrates for the first time that neuroimaging techniques can identify increased pituitary activity. In a study with 11 healthy women sexual orgasm compared to rest caused an increased blood supply to the pituitary. We assume that this increase signifies elevated pituitary activation in order to produce higher plasma concentrations of oxytocin and prolactin. These hormones induce vaginal and uterus movements, ovulation and enhancement of sperm and egg transport. No increased blood supply was observed comparing clitoral stimulation, orgasm attempt, and faked orgasm with rest. In a study with 11 healthy men comparing ejaculation with rest did not reveal increased pituitary activation, probably because ejaculation causes a much lower increase of oxytocin and prolactin plasma concentration than female orgasm.

Circulating prolactin levels and risk of epithelial ovarian cancer

PURPOSE

Indirect evidence from experimental and epidemiological studies suggests that prolactin may be involved in ovarian cancer development. However, the relationship between circulating prolactin levels and risk of ovarian cancer is unknown.

METHODS

We conducted a nested case-control study of 230 cases and 432 individually matched controls within three prospective cohorts to evaluate whether pre-diagnostic circulating prolactin is associated with subsequent risk of ovarian cancer. We also assessed whether lifestyle and reproductive factors are associated with circulating prolactin among controls.

RESULTS

Prolactin levels were significantly lower among post- versus pre-menopausal women, parous versus nulliparous women, and past versus never users of oral contraceptives in our cross-sectional analysis of controls. In our nested case-control study, we observed a non-significant positive association between circulating prolactin and ovarian cancer risk (OR(Q4vsQ1) 1.56, 95 % CI 0.94, 2.63, p trend 0.15). Our findings were similar in multivariate-adjusted models and in the subgroup of women who donated blood ≥5 years prior to diagnosis. We observed a significant positive association between prolactin and risk for the subgroup of women with BMI ≥25 kg/m(2) (OR(Q4vsQ1) 3.10, 95 % CI 1.39, 6.90), but not for women with BMI <25 kg/m(2) (OR(Q4vsQ1) 0.81, 95 % CI 0.40, 1.64).

CONCLUSIONS

Our findings suggest that prolactin may be associated with increased risk of ovarian cancer, particularly in overweight/obese women. Factors associated with reduced risk of ovarian cancer, such as parity and use of oral contraceptives, were associated with lower prolactin levels, which suggests that modulation of prolactin may be a mechanism underlying their association with risk.