Excessive free fatty acid sensing in pituitary lactotrophs elicits steatotic liver disease by decreasing prolactin levels

The pituitary is the central endocrine gland with effects on metabolic dysfunction-associated steatotic liver disease (MASLD). However, it is not clear whether the pituitary responds to free fatty acid (FFA) toxicity, thus dysregulating hepatic lipid metabolism. Here, we demonstrate that decreased prolactin (PRL) levels are involved in the association between FFA and MASLD based on a liver biospecimen-based cohort. Moreover, overloaded FFAs decrease serum PRL levels, thus promoting liver steatosis in mice with both dynamic diet intervention and stereotactic pituitary FFA injection. Mechanistic studies show that excessive FFA sensing in pituitary lactotrophs inhibits the synthesis and secretion of PRL in a cell-autonomous manner. Notably, inhibiting excessive lipid uptake using pituitary stereotaxic virus injection or a specific drug delivery system effectively ameliorates hepatic lipid accumulation by improving PRL levels. Targeted inhibition of pituitary FFA sensing may be a potential therapeutic target for liver steatosis.

Prolactin levels in functional hypothalamic amenorrhea: a retrospective case-control study

PURPOSE

Functional hypothalamic amenorrhea (FHA) is due to hypothalamic dysregulation. Literature lacks data about prolactin in FHA women, although both prolactin levels and FHA are associated with stress. Moreover, polycystic ovarian morphology is common in FHA and there is an association between FHA and polycystic ovary syndrome. Thus, the aim of this study was to assess prolactin levels in FHA patients and controls with a special focus on factors influencing prolactin levels, that could be considered as "sensors" of the hypothalamic-pituitary dysregulation.

METHODS

In a retrospective cohort study, 140 women with clearly defined FHA were compared to 70 healthy, normally ovulating women matched for age. The main outcome parameter was prolactin. Factors associated with prolactin levels > 12 µg/L were tested using a multivariable binary logistic regression model.

RESULTS

The median prolactin level was 11.5 µg/L (interquartile range, IQR 7.5-14.4), which was similar to the control group (median 10.7, IQR 8.3-14.5; p = 0.065). Only two women had hyperprolactinemia (prolactin > 25 µg/L; 1.4%). In a multivariable binary logistic regression model eating disorder (odds ratio, OR 0.206; p = 0.040), excessive exercise (OR 0.280; p = 0.031) and TSH (OR 1.923; p = 0.020) were significantly associated with prolactin levels > 12 µg/L.

CONCLUSION

Women with FHA have similar prolactin levels to healthy age-matched individuals. Eating disorders and excessive exercise where associated with prolactin levels < 12 µg/L, in contrast to TSH.

Population Pharmacodynamic Models of Risperidone on PANSS Total Scores and Prolactin Levels in Schizophrenia

Currently, research predominantly focuses on evaluating clinical effects at specific time points while neglecting underlying patterns within the treatment process. This study aims to analyze the dynamic alterations in PANSS total scores and prolactin levels in patients with schizophrenia treated with risperidone, along with the influencing covariates. Using data from an 8-week randomized, double-blind, multicenter clinical trial, a population pharmacodynamic model was established for the PANSS total scores of and prolactin levels in patients treated with risperidone. The base model employed was the Emax model. Covariate selection was conducted using a stepwise forward inclusion and backward elimination approach. A total of 144 patients were included in this analysis, with 807 PANSS total scores and 531 prolactin concentration values. The PANSS total scores of the patients treated with risperidone decreased over time, fitting a proportionally parameterized sigmoid Emax model with covariates including baseline score, course of the disease, gender, plasma calcium ions, and lactate dehydrogenase levels. The increase in prolactin levels conformed to the ordinary Emax model, with covariates encompassing course of the disease, gender, weight, red blood cell count, and triglyceride levels. The impacts of the baseline scores and the course of the disease on the reduction of the PANSS scores, as well as the influence of gender on the elevation of prolactin levels, each exceeded 20%. This study provides valuable quantitative data regarding PANSS total scores and prolactin levels among patients undergoing risperidone treatment across various physiological conditions.

Comparison of the Effects of Recombinant and Native Prolactin on the Proliferation and Apoptosis of Goose Granulosa Cells

In poultry, prolactin (PRL) plays a key role in the regulation of incubation behavior, hormone secretion, and reproductive activities. However, previous in vitro studies have focused on the actions of PRL in ovarian follicles of poultry, relying on the use of exogenous or recombinant PRL, and the true role of PRL in regulating ovarian granulosa cell (GC) functions in poultry awaits a further investigation using endogenous native PRL. Therefore, in this study, we first isolated and purified recombinant goose PRL protein (rPRL) and native goose PRL protein (nPRL) using Ni-affinity chromatography and rabbit anti-rPRL antibodies-filled immunoaffinity chromatography, respectively. Then, we analyzed and compared the effects of rPRL and nPRL at different concentrations (0, 3, 30, or 300 ng/mL) on the proliferation and apoptosis of both GCs isolated from goose ovarian pre-hierarchical follicles (phGCs) and from hierarchical follicles (hGCs). Our results show that rPRL at lower concentrations increased the viability and proliferation of both phGCs and hGCs, while it exerted anti-apoptotic effects in phGCs by upregulating the expression of Bcl-2. On the other hand, nPRL increased the apoptosis of phGCs in a concentration-dependent manner by upregulating the expressions of caspase-3 and Fas and downregulating the expressions of Bcl-2 and Becn-1. In conclusion, this study not only obtained a highly pure nPRL for the first time, but also suggested a dual role of PRL in regulating the proliferation and apoptosis of goose GCs, depending on its concentration and the stage of follicle development. The data presented here can be helpful in purifying native proteins of poultry and enabling a better understanding of the roles of PRL during the ovarian follicle development in poultry.

Prolactin in Polycystic Ovary Syndrome: Metabolic Effects and Therapeutic Prospects

Polycystic ovary syndrome (PCOS) is the most prevalent endocrine and metabolic disorder in premenopausal women, characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries. Patients frequently present comorbidities, including obesity, insulin resistance, and impaired glucose and lipid metabolism. The diverse clinical presentation may mimic various endocrine disorders, making the diagnosis challenging in some clinical circumstances. Prolactin (PRL) is a recommended biomarker in the initial diagnostic workup to rule out hyperprolactinemia (HPRL). The traditional role of PRL is linked to lactation and the reproductive system. Recent research highlights PRL's emerging role in metabolic homeostasis. PRL influences metabolism directly by interacting with the pancreas, liver, hypothalamus, and adipose tissue. Its influence on an individual's metabolism is intricately tied to its serum concentration. While deficient and very high levels of PRL can negatively affect metabolism, intermediate-normal to moderately high levels may promote metabolic health. In women with PCOS, PRL levels may be altered. Research results on different aspects of the relationship between PCOS and the impact of various levels of PRL on metabolic homeostasis are limited and inconsistent. In this narrative literature review, we comprehensively examined data on serum PRL levels in PCOS patients. We investigated the correlation between a favorable metabolic profile and serum PRL levels in this population. Furthermore, we explored the concept of beneficial PRL effects on metabolism and discussed the potential therapeutic application of dopamine agonists in PCOS treatment. Lastly, we emphasized several promising avenues for future research in this field.

Improved Insulin Secretion Response and Beta-cell Function Correlated with Increased Prolactin Levels After Laparoscopic Sleeve Gastrectomy in Morbidly Obese Patients with Acanthosis Nigricans

OBJECTIVE

To explore insulin secretion patterns, β-cell function, and serum prolactin (PRL) concentrations in Chinese morbidly obese patients with Acanthosis nigricans (AN) and their alterations after laparoscopic sleeve gastrectomy (LSG).

METHODS

A total of 138 morbidly obese subjects undergoing LSG were categorized as simple obesity without AN (OB group, n = 55) and obesity with AN (AN group, n = 83). Oral glucose tolerance test (OGTT), PRL, and related metabolic indices were performed pre- and 12 months post-LSG. Insulin secretion patterns were derived from insulin secretion peak time during OGTT: type I (peak at 30 or 60 min) and type II (peak at 120 or 180 min).

RESULTS

Preoperatively, AN group showed significantly higher proportions of type II insulin secretion pattern, fasting insulin (FINS), and homeostatic model assessment of insulin resistance (HOMA-IR) whereas lower oral glucose insulin sensitivity (OGIS), insulinogenic index (IGI), and disposition index (DI) than OB group, which were improved significantly at 12 months postoperatively in both groups, more pronounced in AN group. Intriguingly, serum PRL declined substantially in AN group than OB group at baseline whereas elevated only in the AN group post-LSG. After adjusting for confounding factors, elevated PRL correlated significantly with increased IGI and DI, and decreased HOMA-IR in both genders, as well as increased OGIS in females, which was detected only in the AN group CONCLUSION: Morbidly obese patients with AN presented delayed insulin secretion response, impaired insulin secretion, and β-cell dysfunction, which were significantly improved by LSG and might benefit from elevated PRL.

Study of Association of Serum Prolactin Levels with Insulin Resistance in Type 2 Diabetes Mellitus Patients

Objective

Prolactin (PRL) regulates glucose metabolism and insulin sensitivity. The study aimed to evaluate the role of PRL in glucose homeostasis and its association with insulin resistance in patients with diabetes mellitus (DM).

Methods and Materials

This cross-sectional, observational study included 100 patients (25-60 years) with T2DM. Primary information including demographics, anthropometric measurements, and biochemical measures (complete blood count, glucose parameters, liver and kidney function test, lipid profile, thyroid function test, serum fasting insulin levels, serum PRL levels) was collected.

Results

A total of 100 patients, 50 men and 50 women (25 premenopausal and 25 postmenopausal), were enrolled in this study. The correlation between serum cholesterol and PRL was found to be statistically non-significant (P = 0.129) in men and significant (P = 0.041) in women. There was an inverse relationship between fasting plasma glucose and serum PRL levels in both men (r = -0.88; P < 0.0001) and women patients (r = -0.768; P < 0.0001). Negative correlation between postprandial plasma glucose and PRL was found to be statistically significant (r = -0.398; P = 0.048) in postmenopausal women. The comparison in both men and women indicated an inverse correlation between serum PRL and glycated haemoglobin levels. There was a significant negative correlation between homeostasis model assessment-estimated insulin resistance (HOMA-IR) and PRL levels in both men (r = -0.362; P = 0.039) and women patients (r = -0.362; P = 0.003). Homeostasis model assessment of β cell function (HOMA-β), which directly correlates with residual pancreatic beta cell function, was positively correlated with prolactin levels, irrespective of gender and menopausal status of female subjects.

Conclusion

Serum PRL levels correlate with improved glycaemic control.

Metabolic Abnormalities, Inflammatory Markers and Endothelial Dysfunction in Hyperprolactinemia due to Prolactinoma before and after Normalization of Serum Prolactin: A Prospective Case Control Study

Background

Hyperprolactinemia is associated with obesity, dyslipidemia, insulin resistance, and low-grade inflammation which may promote endothelial dysfunction (EnD). Limited work has been done on EnD in prolactinomas and we, therefore, studied serum markers of inflammation and EnD in patients with prolactinomas before and after treatment with dopamine agonists.

Methodology

Fifty-six treatment naïve patients with prolactinomas and fifty-three (apparently healthy age and sex-matched) controls were enrolled in the study and subjected to clinical assessment and laboratory investigations including blood glucose, total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, urea, creatinine, uric acid, erythrocyte sedimentation rate (ESR), highly sensitive C-reactive protein (hsCRP) and markers of EnD i.e., intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Patients were treated with a dopamine agonist (cabergoline) and parameters (like ESR, hsCRP, ICAM-1, and VCAM-1) were measured at 12 weeks.

Results

The majority of the patients (84%) were female, more than half (52%) had metabolic syndrome and over a third (36%) were obese. Blood glucose fasting, HbA1c, lipid fractions, ESR, hsCRP, ICAM-1, and VCAM-1 were significantly higher in patients than in controls. Median ICAM-1 was 1331.95 ng/ml (IQR 803.43-1825.99) in patients vs 753.04 ng/ml (IQR 402.04-871.55) in controls, P < 0.001 and median VCAM-1in patients was 971.35 ng/ml (IQR 695.03-1285.23) as against 634.56 ng/ml (IQR 177.49-946.50) in controls, p0.001. Serum ICAM-1 and VCAM-1 correlated positively with hsCRP. On multivariate regression analysis, serum hsCRP was the only significant predictor of change in ICAM-1 and VCAM-1. Normalization of serum PRL with CAB resulted in a significant decrease in metabolic parameters, ESR, hsCRP, ICAM-1, and VCAM-1.

Conclusion

Hyperprolactinemia because of prolactinoma is associated with EnD secondary to systemic inflammation and metabolic abnormalities which improve after treatment with DA.

A Meta-Analysis of Observational Studies on Prolactin Levels in Women with Polycystic Ovary Syndrome

Women with polycystic ovary syndrome (PCOS) are reported to have different levels of prolactin (PRL) compared to women without PCOS. This study aimed to evaluate the PRL levels in women with PCOS, compared to the control group, before and after adjustment for potential confounders. Using a logical combination of keywords, a comprehensive search was carried out in PubMed and Web of Science, from inception to 30 August 2022. Weighted mean differences (WMDs) with corresponding 95% CIs in PRL levels were employed with a random-effects model. I² was applied to evaluate heterogeneity among studies. A meta-regression analysis and subgroup analysis were conducted to explore heterogeneity sources. Publication bias was assessed by the Egger test. Thirty-two studies, measuring PRL levels in 8551 PCOS patients according to the Rotterdam criteria and 13,737 controls, were included in the meta-analysis. Pooled effect size suggested that the overall weighted mean difference (WMD) of PRL level was significantly higher in women with PCOS, compared to controls (WMD = 1.01, 95% CI: 0.04-1.98, p = 0.040). The result of meta-regression adjusted for age, BMI, and the continent of origin, revealed no confounding effect on results. Sub-group analysis of PRL levels according to the continent of origin showed significantly higher PRL levels among Eurasian PCOS patients compared to the control; this difference was not statistically significant in the subgroups of women from Asia, Europe, and South America. In conclusion, PRL levels in patients who were diagnosed according to the Rotterdam criteria were significantly higher than non-PCOS participants. Slightly higher levels of PRL could be presented as a diagnostic feature of PCOS.

The metabolic role of prolactin: systematic review, meta-analysis and preclinical considerations

INTRODUCTION

Hyperprolactinemia has been proven to induce hypogonadism and metabolic derangements in both genders, while the consequences of prolactin (PRL) deficiency have been poorly investigated.

AREAS COVERED

To systematically review and analyze data from clinical studies focusing on the metabolic consequences of abnormally high prolactin levels (HPRL) and low prolactin levels (LPRL). In addition, data from preclinical studies about underlying pathophysiological mechanisms were summarized and discussed.

EXPERT OPINION

PRL contributes to providing the correct amount of energy to support the mother and the fetus/offspring during pregnancy and lactation, but it also has a homeostatic role. Pathological PRL elevation beyond these physiological conditions, but also its reduction, impairs metabolism and body composition in both genders, increasing the risk of diabetes and cardiovascular events. Hence, hypoprolactinemia should be avoided as much as possible during treatment with dopamine agonists for prolactinomas. Patients with hypoprolactinemia, because of endogenous or iatrogenic conditions, deserve, as those with hyperprolactinemia, careful metabolic assessment.

Prolactin as an adrenocorticotropic hormone: Prolactin signalling is a conserved key regulator of sexually dimorphic adrenal gland function in health and disease

A large number of previous reports described an effect of the pituitary hormone prolactin (PRL) on steroid hormone production by the adrenal cortex. However, those studies remained anecdotal and were never converted into a conceptual and mechanistic framework, let alone being translated into clinical care. In the light of our recently published landmark study where we described PRL signalling as a pivotal regulator of the sexually dimorphic adrenal phenotype in mouse and of adrenal androgen production in humans, we present here the overarching hypothesis that PRL signalling increases the activity of Steroidogenic Factor-1 (SF-1/NR5A1), a transcription factor that has an essential role in adrenal gland development and function, to regulate adrenal cortex growth and hormonal production in physiological and pathological conditions. PRL can then be considered as a bona fide adrenocorticotropic hormone synergizing with ACTH in the endocrine control of adrenal cortex function.

Association of Serum Prolactin With Type 2 Diabetes Mellitus: A Comparative Cross-Sectional Study From South India

BACKGROUND

 The association of serum prolactin (PRL) with diabetes is still uncertain, with a paucity of data in the south Indian population. This study aims to compare the serum PRL levels between type 2 diabetes mellitus (T2DM) patients and normoglycaemic volunteers and correlate the serum PRL level with fasting plasma glucose (FPG), postprandial plasma glucose (PPG), glycated haemoglobin (HbA1c) levels, and the lipid profile in the study population.

METHODS

 This was a comparative cross-sectional study among 112 T2DM participants and 112 healthy volunteers in a tertiary care centre in India. All participants were tested for FPG, PPG, HbA1c, fasting serum lipid profile, and serum PRL, which were compared between T2DM patients and healthy volunteers.

RESULTS

 The serum PRL in T2DM patients was significantly lower compared to healthy volunteers (8.67 ± 4.37 vs. 13.76 ± 6.55 ng/ml, P < 0.001). FPG, PPG, and HbA1c correlated inversely with serum PRL in our study population. On multivariable logistic regression adjusted for age and sex, a higher serum PRL level within the physiological range was protective for T2DM (adjusted odds ratio: 0.83, 95% CI: 0.77-0.90, P < 0.001). Serum PRL levels were inversely correlated with serum total cholesterol, low-density lipoprotein cholesterol, and triglycerides, but not with high-density lipoprotein cholesterol.

CONCLUSIONS

A high serum PRL within the physiological range was inversely associated with the prevalence of T2DM in the south Indian population. Serum PRL also correlated inversely with glycaemic and blood lipid parameters. Larger longitudinal studies are required to further validate the association of serum PRL with various components of metabolic syndrome in the south Indian population.

To what extent does polycystic ovary syndrome influence the cut-off value of prolactin? Findings of a community-based study

PURPOSE

Polycystic ovary syndrome (PCOS) and hyperprolactinemia are the most frequent endocrine disorders in women which share several common features. There are inconsistent results regarding the existence of a possible pathophysiological interplay between these endocrinopathies and the elevation of prolactin (PRL) in PCOS. The purpose of this study was to explore the upper reference limit of PRL in PCOS women.

PATIENTS AND METHODS

This study is a cross-sectional analysis using data collected from two population-based PCOS prevalence studies. After considering the exclusion criteria, 216 women with PCOS diagnosed based on the Rotterdam criteria and 702 eumenorrheic non-hirsute controls, were enrolled. The age distribution of PRL and the effect of PCOS on the percentiles of serum PRL were compared between the PCOS group and controls. The possible contributing factors for the elevation of PRL were evaluated.

RESULTS

In the subgroup of women with PCOS, aged ≤35 years, the age-adjusted model of quantile regression revealed a significant elevation of PRL from the 60th percentile onwards, leading to an increase of nearly 10 ​ng/ml (p ​= ​0.023, 95% CI 1.3-17.62) of the 95th percentile of PRL. Hyperprolactinemic PCOS women had higher levels of luteinizing hormone (LH).

CONCLUSIONS

In PCOS women, aged ≤35 years, the upper reference limit of serum PRL was approximately 1.5-fold higher than in controls. The pathway underlying PRL elevation in PCOS might be attributed to a decline in central dopaminergic tone associated with PCOS which leads to an increase in levels of both - PRL and LH.

Polycystic ovary syndrome: clinical and laboratory variables related to new phenotypes using machine-learning models

PURPOSE

Polycystic Ovary Syndrome (PCOS) is the most frequent endocrinopathy in women of reproductive age. Machine learning (ML) is the area of artificial intelligence with a focus on predictive computing algorithms. We aimed to define the most relevant clinical and laboratory variables related to PCOS diagnosis, and to stratify patients into different phenotypic groups (clusters) using ML algorithms.

METHODS

Variables from a database comparing 72 patients with PCOS and 73 healthy women were included. The BorutaShap method, followed by the Random Forest algorithm, was applied to prediction and clustering of PCOS.

RESULTS

Among the 58 variables investigated, the algorithm selected in decreasing order of importance: lipid accumulation product (LAP); abdominal circumference; thrombin activatable fibrinolysis inhibitor (TAFI) levels; body mass index (BMI); C-reactive protein (CRP), high-density lipoprotein cholesterol (HDL-c), follicle-stimulating hormone (FSH) and insulin levels; HOMA-IR value; age; prolactin, 17-OH progesterone and triglycerides levels; and family history of diabetes mellitus in first-degree relative as the variables associated to PCOS diagnosis. The combined use of these variables by the algorithm showed an accuracy of 86% and area under the ROC curve of 97%. Next, PCOS patients were gathered into two clusters in the first, the patients had higher BMI, abdominal circumference, LAP and HOMA-IR index, as well as CRP and insulin levels compared to the other cluster.

CONCLUSION

The developed algorithm could be applied to select more important clinical and biochemical variables related to PCOS and to classify into phenotypically different clusters. These results could guide more personalized and effective approaches to the treatment of PCOS.

The beneficial metabolic actions of prolactin

The role of prolactin (PRL) favoring metabolic homeostasis is supported by multiple preclinical and clinical studies. PRL levels are key to explaining the direction of its actions. In contrast with the negative outcomes associated with very high (>100 μg/L) and very low (<7 μg/L) PRL levels, moderately high PRL levels, both within but also above the classically considered physiological range are beneficial for metabolism and have been defined as HomeoFIT-PRL. In animal models, HomeoFIT-PRL levels counteract insulin resistance, glucose intolerance, adipose tissue hypertrophy and fatty liver; and in humans associate with reduced prevalence of insulin resistance, fatty liver, glucose intolerance, metabolic syndrome, reduced adipocyte hypertrophy, and protection from type 2 diabetes development. The beneficial actions of PRL can be explained by its positive effects on main metabolic organs including the pancreas, liver, adipose tissue, and hypothalamus. Here, we briefly review work supporting PRL as a promoter of metabolic homeostasis in rodents and humans, the PRL levels associated with metabolic protection, and the proposed mechanisms involved. Finally, we discuss the possibility of using drugs elevating PRL for the treatment of metabolic diseases.

The Effect of Leptin on the Regulation of Immune Responses in Women with Polycystic Ovary Syndrome

&lt;b&gt;Background and Objective:&lt;/b&gt; Leptin is a hormone produced by fat cells in adipose tissue that plays a biological role in metabolism, immune system control and energy flow regulation. The study's objective was to investigate serum leptin levels in PCOS females and determine how they are related to immunological and hormonal parameters. &lt;b&gt;Materials and Methods:&lt;/b&gt; Thirty PCOS women were chosen for the study and compared to thirty healthy women as control samples, with both case and normal samples ranging in age from 18-36 years. WBC count, absolute numbers of neutrophils, lymphocytes, monocytes, eosinophils, leptin, Prolactin and serum IgA levels were measured. &lt;b&gt;Results:&lt;/b&gt; The results showed the mean WBC, lymphocytes and eosinophil absolute numbers in PCOS women were significantly different. However, there was no significant difference in the absolute numbers of neutrophils and monocytes. The findings also revealed a significant increase in BMI, IgA, leptin and prolactin levels in PCOS when compared to controls. The results showed strong positive correlation coefficients between BMI and IgA (1.000**), WBC with neutrophils, lymphocytes and monocytes (0.797**, 0.790**, 0.712**), respectively and finally leptin and prolactin (0.474**). The same test, on the other hand, revealed an inverse correlation coefficient between BMI, IgA and prolactin (-0.376*, -0.376*, respectively with p&lt;u&gt;<&lt;/u&gt;0.05). &lt;b&gt;Conclusion:&lt;/b&gt; A rise in the levels of the hormones leptin and prolactin, which were positively associated with the body mass index in women with PCOS, was found in the current study. The findings revealed that the hormones leptin and prolactin have an effect on some immune parameters in women with PCOS.

Metabolic effects of prolactin and the role of dopamine agonists: A review

Prolactin is a polypeptide hormone that is well known for its role in reproductive physiology. Recent studies highlight its role in neurohormonal appetite regulation and metabolism. Elevated prolactin levels are widely associated with worsening metabolic disease, but it appears that low prolactin levels could also be metabolically unfavorable. This review discusses the pathophysiology of prolactin related metabolic changes, and the less commonly recognized effects of prolactin on adipose tissue, pancreas, liver, and small bowel. Furthermore, the effect of dopamine agonists on the metabolic profiles of patients with hyperprolactinemia are discussed as well.

Cortisol and polycystic ovarian syndrome - a systematic search and meta-analysis of case-control studies

BACKGROUND

Polycystic ovarian syndrome (PCOS) has become an emerging disorder affecting women of reproductive age group. Its intricate presentation of signs and symptoms makes it a disease of interest to research. While there are varied hypotheses related to its cause and pathogenesis, role of stress in this disease is yet to be grounded. There is emerging body of evidence on cortisol and PCOS, although it is currently equivocal.

METHODS

Medline, Embase, Pubmed, Science Direct, Google Scholar, and Scopus were searched from March 1985 to March 2020 using MeSH terms. After dual quality assessments and data abstraction, the final articles were included for meta-analysis.

RESULTS

Forty-one studies qualified for the analysis. Pooled meta-analysis showed that the level of cortisol was significantly higher in PCOS when compared to healthy controls (standard mean difference [SMD] = 0.83, 95% confidence interval [CI] = 0.42-1.23) with highly significant heterogeneity (I² = 94%). Subgroup analysis done based on type of sample stated high effect size for blood cortisol levels (SMD = 0.9, 95%CI = 0.32; 1.51) compared to overall effect.

CONCLUSIONS

This systematic review and meta-analysis on cortisol and PCOS have helped in generating evidence regarding the role of cortisol in the pathogenesis of PCOS and the use of cortisol estimation as a potential stress marker in PCOS.

Prolactin, metabolic and immune parameters in naïve subjects with a first episode of psychosis

BACKGROUND

Prolactin (Prl) is a pleiotropic hormone initially described for its regulation of lactation in mammals but later associated with metabolic and immune homeostasis, stress, inflammatory response and human behavior. Its regulation through dopamine receptors highlights its importance in psychiatry mostly because hyperprolactinemia is a common secondary side effect of dopamine antagonists. Despite its undeciphered patho-physiological mechanisms, hyperprolactinemia in naïve psychosis patients has been widely described. Its consequences might underlie the increased morbidity and early mortality found in naïve subjects as described in the general population where prolactin values have been correlated with inflammatory, immune and metabolic parameters.

METHODS

We aimed to evaluate the correlation between prolactin values and other biochemical parameters (C-reactive Protein-CrP, blood cell count, lipid and hepatic profile, fasting glucose) in a cohort of first episode psychosis naïve subjects (N = 491) stratified by sex. Regression analyses with confounders were performed to evaluate the association.

FINDINGS

Prl displayed significant correlations with C-Reactive Protein (CrP), Low-Density Lipoprotein (LDL), Aspartate Transaminase (AST) for females and High-Density Lipoprotein (HDL) and eosinophil count for males. However, and despite previous specific sex correlations, significant associations were described for CrP, HDL, LDL, AST and ALT without sex interaction and despite confounders such as age, Body Mass Index or smoking status.

CONCLUSIONS

Our results show a specific relation of Prl with immune and metabolic parameters describing a heterogeneous pattern. Our results suggest that prolactin might underlie the excess of morbidity and early mortality in naïve patients through a specific pathway.

Higher blood pressure in normal weight women with PCOS compared to controls

OBJECTIVE

Obesity is considered to be the strongest predictive factor for cardio-metabolic risk in women with polycystic ovary syndrome (PCOS). The aim of the study was to compare blood pressure (BP) in normal weight women with PCOS and controls matched for age and BMI.

METHODS

From a Nordic cross-sectional base of 2615 individuals of Nordic ethnicity, we studied a sub cohort of 793 normal weight women with BMI < 25 kg/m2 (512 women with PCOS according to Rotterdam criteria and 281 age and BMI-matched controls). Participants underwent measurement of BP and body composition (BMI, waist-hip ratio), lipid status, and fasting BG. Data were presented as median (quartiles).

RESULTS

The median age for women with PCOS were 28 (25, 32) years and median BMI was 22.2 (20.7, 23.4) kg/m2. Systolic BP was 118 (109, 128) mmHg in women with PCOS compared to 110 (105, 120) mmHg in controls and diastolic BP was 74 (67, 81) vs 70 (64, 75) mmHg, both P < 0.001. The prevalence of women with BP ≥ 140/90 mmHg was 11.1% (57/512) in women with PCOS vs 1.8% (5/281) in controls, P < 0.001. In women ≥ 35 years the prevalence of BP ≥ 140/90 mmHg was comparable in women with PCOS and controls (12.7% vs 9.8%, P = 0.6). Using multiple regression analyses, the strongest association with BP was found for age, waist circumference, and total cholesterol in women with PCOS.

CONCLUSIONS

Normal weight women with PCOS have higher BP than controls. BP and metabolic screening are relevant also in young normal weight women with PCOS.

Prolactin Is Associated With Insulin Resistance and Beta-Cell Dysfunction in Infertile Women With Polycystic Ovary Syndrome

BACKGROUND

Our study aimed to investigate if serum prolactin (PRL) levels associated with insulin resistance and beta-cell dysfunction in infertile patients with polycystic ovary syndrome (PCOS).

METHODS

This was a retrospective cross-sectional study performed in the reproductive medicine center of the first affiliated hospital of Wenzhou Medical University. From January 2007 to August 2018, a total of 792 PCOS and 700 non-PCOS infertile women were included. All patients' prolactin levels were in the normal range. PCOS was diagnosed according to the Rotterdam Criteria. Anthropometric parameters, blood pressure, serum prolactin levels, sex hormones, fasting lipids, fasting plasma glucose (FPG), fasting insulin (FINS) and hepatic biological parameters were measured in all subjects.

RESULTS

Serum prolactin levels in PCOS women were significantly decreased compared with levels in non-PCOS women after adjusting for age and BMI (P < 0.05). Moreover, we found that prolactin levels were positively associated with high-density lipoprotein cholesterol (HDL-C) and negatively associated with age, BMI, waist circumference (WC), hip circumference (HC), luteinizing hormone/follicle stimulating hormone (LH/FSH), estradiol (E₂), FINS, homeostasis model assessment of insulin resistance (HOMA-IR), homeostasis model assessment of β (HOMA-β), triglyceride (TG) and alanine aminotransferase (ALT) (P < 0.05). After adjusting for age and BMI, multiple linear regression analysis revealed that LH, LH/FSH, E₂, FINS, HOMA-IR, and HOMA-β were negatively associated with serum PRL (P < 0.05).

CONCLUSIONS

Low serum PRL levels within the normal range associates with a higher incidence of insulin resistance and beta-cell dysfunction in infertile women with PCOS.

Time for a New Perspective on Prolactin in Metabolism

The pituitary hormone prolactin (PRL) regulates a variety of functions beyond reproduction. The association between physiological (pregnancy) and pathological (prolactinoma) hyperprolactinemia and metabolic alterations led to the concept of this hormone being diabetogenic. However, large cohort clinical studies have recently shown that low circulating PRL levels are associated with metabolic disease and represent a risk factor for type 2 diabetes (T2D), whereas high PRL levels are beneficial. Moreover, PRL acts on the pancreas, liver, adipose tissue, and hypothalamus to maintain and promote metabolic homeostasis. By integrating basic and clinical evidence, we hypothesize that upregulation of PRL levels is a mechanism to maintain metabolic homeostasis and, thus, propose that the range of PRL levels considered physiological should be expanded to higher values.

Low prolactin levels are associated with visceral adipocyte hypertrophy and insulin resistance in humans

PURPOSE

Low prolactin (PRL) serum levels are associated with glucose intolerance and type 2 diabetes in adults, and with metabolic syndrome and obesity in children. In obese rodents, PRL treatment promotes insulin sensitivity by maintaining adipose tissue fitness, and lack of PRL signaling exacerbates obesity-derived metabolic alterations. Since adipose tissue dysfunction is a key factor triggering metabolic alterations, we evaluated whether PRL serum levels are associated with adipocyte hypertrophy (a marker of adipose tissue dysfunction), insulin resistance, and metabolic syndrome in lean, overweight, and obese adult men and women.

METHODS

Samples of serum and adipose tissue from 40 subjects were obtained to evaluate insulin resistance index (homeostasis model assessment of insulin resistance (HOMA-IR)), signs of metabolic syndrome (glucose levels, high-density lipoproteins, triglycerides, blood pressure, and waist circumference), as well as adipocyte size and gene expression in fat.

RESULTS

Lower PRL serum levels are associated with adipocyte hypertrophy, in visceral but not in subcutaneous fat, and with a higher HOMA-IR. Furthermore, low systemic PRL levels together with high waist circumference predict an elevated HOMA-IR whereas low serum PRL values in combination with high blood glucose predicts visceral adipocyte hypertrophy. In agreement, visceral fat from insulin resistant subjects shows reduced expression of prolactin receptor. However, there is no association between PRL levels and obesity or signs of metabolic syndrome.

CONCLUSIONS

Our results support that low levels of PRL are markers of visceral fat dysfunction and insulin resistance, and suggest the potential therapeutic value of medications elevating PRL levels to help maintain metabolic homeostasis.

The Association Between Prolactin and Metabolic Parameters in PCOS Women: A Retrospective Analysis

Background: The aim of this retrospective study was to analyze the association between prolactin (PRL) and metabolic parameters in infertile patients with polycystic ovary syndrome (PCOS). Methods: A total of 2,052 patients with PCOS and 9,696 patients with tubal infertility (non-PCOS) undergoing in vitro fertilization and embryo transfer (IVF-ET) at the reproductive medicine center of the first affiliated hospital of Wenzhou Medical University from January 2007 to July 2017 were enrolled in this study. Serum PRL, basic endocrine hormones, fasting plasma lipid, fasting plasma glucose (FPG), liver function, thyroid hormone and other parameters were measured and analyzed. Result: PRL levels were significantly lower in PCOS patients than controls over all age groups (p < 0.05). In the PCOS patients, serum PRL was significantly and positively correlated with FPG, serum TSH and serum FT4, and significantly and negatively correlated with LH, LH/FSH, TC, TG, LDL-C, AST, ALT, γ-GGT, FT3, and FT3/FT4 (p < 0.05 or 0.01). After adjusted for age and body mass index (BMI), serum PRL was positively correlated with FPG, TSH, and FT4, and negatively correlated with LH and LH/FSH. Conclusion: Low serum PRL may be an important cause of metabolic risk in infertile patients with PCOS.

Prolactin and breast increase during pregnancy in PCOS: linked to long-term metabolic health?

Objective To explore whether gestational prolactin and breast increase are markers of metabolic health in pregnancy and on long-term, in PCOS. Design Follow-up study. Women with PCOS, according to the Rotterdam criteria (n = 239), former participants of the randomized controlled trial (RCT) PregMet were invited, 131 participated in the current follow-up study, at mean 8 years after pregnancy. Methods Metformin 2000 mg/day or placebo from first trimester to delivery in the original RCT. No intervention in the current study. Prolactin was analyzed in the first trimester and at gestational week 32 and metabolic characteristics which are part of the metabolic syndrome and measures of glucose homeostasis were examined. Metabolic health was also evaluated according to breast increase versus lack of breast increase during pregnancy. Results Prolactin increase in pregnancy was negatively correlated to BMI (P = 0.007) and systolic blood pressure (P ≤ 0.001) in gestational week 32. Prolactin at gestational week 32 was negatively correlated to BMI (P = 0.044) and visceral fat area (P = 0.028) at 8-year follow-up in an unadjusted model. Prolactin at gestational week 32 showed no associations to metabolic health at follow-up when baseline BMI was adjusted for. Women who reported lack of breast increase during pregnancy, had higher BMI (P = 0.034), waist-hip ratio (P = 0.004), visceral fat area (P = 0.050), total cholesterol (P = 0.022), systolic (P = 0.027) and diastolic blood pressure (P = 0.011) at 8-year follow-up. Conclusion High prolactin levels and breast increase in pregnancy were associated with a more favorable long-term metabolic health in women with PCOS. Both prolactin and breast increase may be mediated by gestational BMI.

Co-shared genetics and possible risk gene pathway partially explain the comorbidity of schizophrenia, major depressive disorder, type 2 diabetes, and metabolic syndrome

Schizophrenia (SCZ) and major depressive disorder (MDD) in treatment-naive patients are associated with increased risk for type 2 diabetes (T2D) and metabolic syndrome (MetS). SCZ, MDD, T2D, and MetS are often comorbid and their comorbidity increases cardiovascular risk: Some risk genes are likely co-shared by them. For instance, transcription factor 7-like 2 (TCF7L2) and proteasome 26S subunit, non-ATPase 9 (PSMD9) are two genes independently reported as contributing to T2D and SCZ, and PSMD9 to MDD as well. However, there are scarce data on the shared genetic risk among SCZ, MDD, T2D, and/or MetS. Here, we briefly describe T2D, MetS, SCZ, and MDD and their genetic architecture. Next, we report separately about the comorbidity of SCZ and MDD with T2D and MetS, and their respective genetic overlap. We propose a novel hypothesis that genes of the prolactin (PRL)-pathway may be implicated in the comorbidity of these disorders. The inherited predisposition of patients with SCZ and MDD to psychoneuroendocrine dysfunction may confer increased risk of T2D and MetS. We illustrate a strategy to identify risk variants in each disorder and in their comorbid psychoneuroendocrine and mental-metabolic dysfunctions, advocating for studies of genetically homogeneous and phenotype-rich families. The results will guide future studies of the shared predisposition and molecular genetics of new homogeneous endophenotypes of SCZ, MDD, and metabolic impairment.

Prolactin improves hepatic steatosis via CD36 pathway

BACKGROUND & AIMS

Prolactin (PRL) is a multifunctional polypeptide with effects on metabolism, however, little is known about its effect on hepatic steatosis and lipid metabolism. Herein, we aimed to assess the role of PRL in the development of non-alcoholic fatty liver disease (NAFLD).

METHODS

The serum PRL levels of 456 patients with NAFLD, 403 controls without NAFLD diagnosed by ultrasound, and 85 individuals with liver histology obtained during metabolic surgery (44 female and 30 male patients with NAFLD and 11 age-matched non-NAFLD female individuals) were evaluated. The expression of the gene encoding the prolactin receptor (PRLR) and signalling molecules involved in hepatic lipid metabolism were evaluated in human liver and HepG2 cells. The effects of overexpression of PRLR or fatty acid translocase (FAT)/CD36 or knockdown of PRLR on hepatic lipid metabolism were tested in free fatty acid (FFA)-treated HepG2 cells.

RESULTS

Circulating PRL levels were lower in individuals with ultrasound-diagnosed NAFLD (men: 7.9 [range, 5.9-10.3] µg/L; women: 8.7 [range, 6.1-12.4] µg/L) than those with non-NAFLD (men: 9.1 [range, 6.8-13.0] µg/L, p = 0.002; women: 11.6 [range, 8.2-16.1] µg/L, p <0.001). PRL levels in patients with biopsy-proven severe hepatic steatosis were lower compared with those with mild-to-moderate hepatic steatosis in both men (8.3 [range, 5.4-9.5] µg/L vs. 9.7 [range, 7.1-12.3] µg/L, p = 0.031) and women (8.5 [range, 4.2-10.6] µg/L vs. 9.8 [range, 8.2-15.7] µg/L, p = 0.027). Furthermore, hepatic PRLR gene expression was significantly reduced in patients with NAFLD and negatively correlated with CD36 gene expression. In FFA-induced HepG2 cells, PRL treatment or PRLR overexpression significantly reduced the expression of CD36 and lipid content, effects that were abrogated after silencing of PRLR. Furthermore, overexpression of CD36 significantly reduced the PRL-mediated improvement in lipid content.

CONCLUSIONS

Our results reveal a novel association between the central nervous system and the liver, whereby PRL/PRLR improved hepatic lipid accumulation via the CD36 pathway.

LAY SUMMARY

Our clinical study suggests a negative association between prolactin (PRL)/prolactin receptor (PRLR) and the presence of non-alcoholic fatty liver disease (NAFLD). Using cell experiments, we found that PRL ameliorates hepatic steatosis via the hepatic PRLR and fatty acid translocase (FAT)/CD36, a key transporter of free fatty acid uptake in liver. Our findings suggest a novel approach to improving NAFLD using PRL and PRLR. Clinical trial number: NCT03296605.

Differential DNA methylation patterns of polycystic ovarian syndrome in whole blood of Chinese women

As a universally common endocrinopathy in women of reproductive age, the polycystic ovarian syndrome is characterized by composite clinical phenotypes reflecting the contributions of reproductive impact of ovarian dysfunction and metabolic abnormalities with widely varying symptoms resulting from interference of the genome with the environment through integrative biological mechanisms including epigenetics. We have performed a genome-wide DNA methylation analysis on polycystic ovarian syndrome and identified a substantial number of genomic sites differentially methylated in the whole blood of PCOS patients and healthy controls (52 sites, false discovery rate < 0.05 and corresponding p value < 5.68e–06), highly consistently replicating biological pathways extensively implicated in immunity and immunity-related inflammatory disorders (false discovery rate < 0.05) that were reportedly regulated in the DNA methylome from ovarian tissue under PCOS condition. Most importantly, our genome-wide profiling focusing on PCOS patients revealed a large number of DNA methylation sites and their enriched functional pathways significantly associated with diverse clinical features (levels of prolactin, estradiol, progesterone and menstrual cycle) that could serve as novel molecular basis of the clinical heterogeneity observed in PCOS women.

Association between serum prolactin levels and insulin resistance in non-diabetic men

Prolactin (PRL) has roles in various physiological functions. Although experimental studies showed that PRL has both beneficial and adverse effects on type 2 diabetes mellitus, clinical findings in subjects with hyperprolactinemia indicate adverse effects on glucose metabolism. However, effects of PRL within the physiological range in human are controversial. A population-based study of 370 Japanese men enrolled in the 2014 Iwaki study (aged 52.0 ± 14.8 years). In this cross-sectional study, associations between serum PRL levels and homeostatic model assessment (HOMA) indices representing glucose metabolism in a physiological setting were examined using multivariable regression analysis. Although univariate linear regression analyses showed significant associations between serum PRL levels and HOMA indices, adjustment with multiple factors made the association with HOMA-ß (insulin secretion) insignificant, while those with HOMA-R (insulin resistance) remained significant (ß = 0.084, p = 0.035). Non-linear regression analyses showed a regression curve with a peak at serum PRL level, 12.4 ng/mL and a positive association of serum PRL level with HOMA-R below the peak (ß = 0.119, p = 0.004). Higher serum PRL levels within the physiological range seem to be associated with insulin resistance in men.

Hyperprolactinemia and Hirsutism in Patients Without Polycystic Ovary Syndrome

Background:

Hirsutism is one of the most important diseases that lead women to refer to dermatology clinic. Hyperprolactinemia is one of the causes of hirsutism. The aim of this study was to determine prolactin (PRL) levels in hirsute women.

Materials and Methods:

In this cross-sectional study, hirsute patients were evaluated. For all of the patients, 2 or 3 days after mense starting, hormone level tests were performed, and 200 patients that had not polycystic ovary syndrome enrolled to the study. A questionnaire of history and physical examination were performed. Data have been analyzed with SPSS version 21.

Results:

Hyperprolactinemia were seen in 25 patients (12.5%). There was no significant relation between marital statuses, galactorrhoea, positive family history, and infertility with hyperprolactinemia. But significant relation was seen between irregular mense and hyperprolactinemia.

Conclusion:

Although hyperprolactinemia is the rare cause of hirsutism, the prevalence of hyperprolactinemia was high in our study. Thus, PRL level in hirsute patients should be evaluate.

Circulating Prolactin and Risk of Type 2 Diabetes: A Prospective Study

Prolactin plays an important role in maintaining a normal glucose homeostasis during pregnancy and beyond. Studies investigating the association between prolactin and type 2 diabetes beyond pregnancy are rare and none is prospective. We aimed to examine whether prolactin associates with type 2 diabetes prospectively in a Chinese population. In 2009, 2,377 participants aged 40 years or older were enrolled from Shanghai, China. Among 1,596 diabetes-free participants at baseline, 1,510 completed the follow-up investigation in 2013. Participants who had a fasting plasma glucose ≥126 mg/dL and/or a 2-hour plasma glucose ≥200 mg/dL during a 75-g oral glucose tolerance test had a definite diagnosis of type 2 diabetes or received antidiabetic therapies during follow-up were classified as having type 2 diabetes. During a mean follow-up of 3.7 years, 189 new cases of type 2 diabetes were documented. After multivariate adjustment, women in the highest quartile of prolactin showed the lowest risk for diabetes compared with those in the lowest quartile (hazard ratio = 0.48, 95% confidence interval: 0.26, 0.90). However, such significant associations were not observed in men. Prolactin may be a mediator in the pathogenesis of type 2 diabetes in women; however, more studies are needed to elucidate the underlying sex-specific mechanism.

Fracture Risk Is Decreased in Women With Polycystic Ovary Syndrome: A Register-Based and Population-Based Cohort Study

Hyperandrogenism, obesity, and hyperinsulinemia may protect against osteoporosis, whereas amenorrhea, increased cortisol, and low growth hormone may be associated with higher fracture risk in polycystic ovary syndrome (PCOS). The objective of this study was to investigate fracture risk in PCOS. In the PCOS Denmark study, women with PCOS and/or hirsutism were identified in the Danish National Patient Register (1995-2012). Each patient was assigned three age-matched controls on the index date of PCOS diagnosis. Individuals with a previous endocrine diagnosis were excluded. Within PCOS Denmark, we embedded a well-characterized subcohort of patients, PCOS OUH, diagnosed with PCOS at Odense University Hospital (n = 1217). We identified incident fractures by International Classification of Diseases, 10th Revision (ICD-10) codes and used conditional Cox regression analyses to compare fracture risk. In the PCOS Denmark study, there were 19,199 women with PCOS and 57,483 controls were included, mean age 30.6 years (range, 12-60 years). Fracture rates were decreased in PCOS Denmark (10.3/1000 patient years) versus controls (13.6/1000 patient years). The adjusted ORs were 0.76 (95% CI, 0.71 to 0.80) for all fractures, 0.82 (95% CI, 0.74 to 0.92) for major osteoporotic fractures, and 0.57 (95% CI, 0.47 to 0.70) for fractures of head and face. The risk reduction was more pronounced below the age of 30 years at diagnosis. Women with PCOS had significant more hospital contacts due to strains and sprains. In the PCOS OUH subcohort, the risk reduction of fractures did not differ between PCOS women with elevated versus normal testosterone levels and the risk reduction was nominally smaller in overweight versus normal weight PCOS women. Women with PCOS had reduced risk of fractures, in particular of the appendicular skeleton. The risk reduction was greater in women with younger age at diagnosis suggesting that the skeletal effects of PCOS may be greater in women who have not yet reached peak bone mass. Reduced participation in sports activities was probably not the reason for the reduced risk of fractures.

Assessment of serum prolactin levels in acute myocardial infarction: The role of pharmacotherapy

BACKGROUND

Hyperprolactinemia may reflect neuroendocrine stress reaction against acute coronary syndromes.

AIM

The aim of the present study was evaluation of the serum prolactin level in the acute myocardial infarction (MI) regarding the current pharmacotherapy in management of MI.

SETTING AND DESIGN

Cross-sectional clinical based study.

SUBJECTS AND METHODS

This cross-sectional clinical study involved all patients with acute MI in a coronary care unit, a total number of 44 patients (45% males and 55% females) with age ranged from 40 to 75 years. A full history for modifiable risk factors and current therapy with aspirin, clopidogrel and or metformin, all patients are nonsmokers. The anthropometric measurements; for estimations of body mass index (kg/m(2)), electrocardiography was obtained. Fasting blood samples were taken in the morning from all patients and the sera used for estimations of routine investigation and determination of ischemic cardiac biomarkers like cardiac troponin I (cTnI) and serum prolactin level.

RESULTS

This study shows a significant increase in the serum prolactin in acute MI as compared with the control. In acute MI serum cTnI elevation was correlated with serum prolactin increments. In metformin-treated group, there was a lowest prolactin serum level.

CONCLUSIONS

Serum prolactin level increased in acute MI, and positively correlated with cardiac troponin level and reflects underlying cardiovascular complications.