Glucose Abnormalities Associated to Prolactin Secreting Pituitary Adenomas

Polycystic Ovary Syndrome in the Context of Pituitary Adenomas: Prevalence, Pathophysiology and Clinical Management

OBJECTIVE

Many review articles have explored data regarding the coexistence of specific types of pituitary adenomas (PAs) and polycystic ovary syndrome (PCOS), particularly focusing on the potential pathogenesis of this intersection and overlapping features. However, a comprehensive evaluation encompassing the full spectrum of PAs and their association with PCOS remains lacking. This review aims to provide a broad assessment of the interactions between these entities, emphasizing pathophysiological mechanisms, clinical presentations, diagnostic challenges and therapeutic implications.

METHODS

A comprehensive literature search was conducted in the PubMed/MEDLINE database, focusing primarily on publications from the years 2000 to 2024, while also including seminal papers from the 1950s. The reference lists of selected articles were also manually searched. Inclusion criteria encompassed review articles, retrospective studies, clinical trials, case reports and meta-analyses providing data on the pathogenesis, clinical features, diagnostic challenges and therapeutic approaches related to PCOS and different PAs.

RESULTS

PCOS and functioning PAs often exhibit overlapping clinical features, complicating diagnosis and management. PCOS may precede and delay the diagnosis of growth hormone (GH)-secreting adenomas. The prevalence of PCOS or its features in acromegaly is influenced by disease activity, while approximating 13% in cases with controlled disease. Excess GH and insulin-like growth factor 1 (IGF-1) adversely affect ovarian function through direct pathways and by inducing insulin resistance, contributing to acromegaly-associated PCOS. In Cushing's syndrome (CS), findings consistent with PCOS may be present in 46% of patients, with cortisol excess contributing to menstrual dysfunction, hyperandrogenism and insulin resistance. While the prevalence of PCOS in patients with prolactinomas remains under-researched, recent studies indicate a 2.8%-10% prevalence of prolactinomas in PCOS. Elevated prolactin (PRL) levels in these patients may promote insulin resistance, further contributing to PCOS pathogenesis. Moreover, increased androgen bioavailability may be observed in all three aforementioned adenomas. To date, no studies have provided prevalence data for PCOS in other types of PAs.

CONCLUSIONS

Distinct clinical features, along with biochemical evaluations and imaging, can help differentiate the presence of both PAs and PCOS. Moreover, excluding other mimicking disorders is essential for an accurate diagnosis of PCOS. The persistence or recurrence of menstrual dysfunction, hyperandrogenism and metabolic disturbances in patients with controlled functioning adenomas may indicate a coexisting PCOS diagnosis. Timely diagnosis may optimize management and improve long-term outcomes for both conditions. Future studies should focus on investigating the clinical differences between patients with co-occurring PCOS and PAs compared to those with PCOS alone, ideally in larger cohorts, to better understand unique diagnostic and therapeutic considerations.

The Influence of Concurrent Autoimmune Thyroiditis on the Cardiometabolic Consequences of Cabergoline in Postmenopausal Women

Background: Untreated hyperprolactinemia and autoimmune thyroiditis (Hashimoto's disease) seem to increase cardiometabolic risk. The cardiometabolic effects of cabergoline were less significant in young women with concurrent euthyroid Hashimoto's illness. This study sought to investigate if the detrimental effects of this condition on cabergoline efficacy are also evident in postmenopausal women. Methods: The study comprised 50 postmenopausal women exhibiting increased prolactin levels, with half qualifying for euthyroid Hashimoto's illness. The subjects with thyroid autoimmunity were matched with those without thyroid disease according to age, body mass index, and prolactin levels. In addition to prolactin, we assessed thyroid-stimulating hormone (TSH), thyroid antibodies, and glucose homeostasis markers: fasting glucose, the homeostatic model assessment 1 of insulin resistance ratio (HOMA1-IR), and glycated hemoglobin (HbA1c). Furthermore, we assessed plasma lipids, plasma uric acid levels, high-sensitivity C-reactive protein (hsCRP), fibrinogen, homocysteine, and the urine albumin-to-creatinine ratio (UACR). The decadal cardiovascular risk was assessed with the Framingham Risk Score (FRS). Results: Before therapy, disparities existed among groups in HOMA1-IR, HDL cholesterol, antibody titers, uric acid, hsCRP, fibrinogen, homocysteine, UACR, and FRS. After six months of treatment, cabergoline successfully corrected prolactin levels (both total and monomeric) in women without thyroid disorders. This normalization correlated with decreases in HOMA1-IR, triglycerides, uric acid, hsCRP, fibrinogen, homocysteine, UACR, and FRS, as well as an elevation in HDL cholesterol. In women diagnosed with Hashimoto's disease, cabergoline's effects were limited to a reduction in prolactin levels, HOMA1-IR, and UACR, as well as an elevation in HDL cholesterol, with these alterations being less pronounced compared to women without thyroid illness. Conclusions: The cardiometabolic benefits of cabergoline were associated with the degree of prolactin concentration reduction. In women diagnosed with Hashimoto's disease, connections were noted between baseline levels and treatment-induced alterations in hsCRP. These data indicate that concurrent euthyroid autoimmune thyroiditis mitigates the cardiometabolic consequences of cabergoline.

Cardiometabolic effects of hypoprolactinemia

The fall of PRL levels below the lower limit of the normal range configures the condition of hypoprolactinemia. Unlike PRL excess, whose clinical features and treatments are well established, hypoprolactinemia has been only recently described as a morbid entity requiring prompt identification and proper therapeutic approach. Particularly, hypoprolactinemia has been reported to be associated with the development of metabolic syndrome and impaired cardiometabolic health, as visceral obesity, insulin-resistance, diabetes mellitus, dyslipidaemia, chronic inflammation, and sexual dysfunction have been found more prevalent in patients with hypoprolactinemia as compared to those with normoprolactinemia. This evidence has been collected mainly in patients on chronic treatment with dopamine agonists for PRL excess due to a PRL-secreting pituitary tumour, and less frequently in those receiving the atypical antipsychotic aripiprazole. Nowadays, hypoprolactinemia appears to represent a novel and unexpected risk factor for cardiovascular diseases, as is the case for hyperprolactinemia. Nevertheless, current knowledge still lacks an accurate biochemical definition of hypoprolactinemia, since no clear PRL threshold has been established to rule in the diagnosis of PRL deficiency enabling early identification of those individual subjects with increased cardiovascular risk directly ascribable to the hormonal imbalance. The current review article focuses on the effects of hypoprolactinemia on the modulation of body weight, gluco-insulinemic and lipid profile, and provides latest knowledge about potential cardiovascular outcomes of hypoprolactinemia.

Risk Assessment of Diabetes Mellitus During and After Pregnancy in Women With Prolactinomas

CONTEXT

Prolactin (PRL) is a crucial mediator of glucoinsulinemic metabolism.

OBJECTIVE

This work aims to dissect glucose metabolism during and after pregnancy in patients with prolactinomas.

METHODS

A total of 52 patients treated with cabergoline (CAB) were evaluated before conception, during pregnancy, and up to 10 years after delivery. During pregnancy, CAB was discontinued, while it was restarted in 57.7% of patients after delivery, due to recurrent hyperprolactinemia (RH). Hormonal (serum PRL) and metabolic (glycated hemoglobin A1c [HbA1c], fasting glucose [FG], glucose tolerance) parameters were assessed.

RESULTS

During pregnancy, PRL gradually increased, while FG remained stable. An inverse correlation between PRL and FG was found in the first (P = .032) and third (P = .048) trimester. PRL percentage increase across pregnancy was inversely correlated with third-trimester FG. Serum PRL before conception emerged as a predictive biomarker of third-trimester FG (t = 2.603; P = .048). Older patients with lower HbA1c in the first trimester and lower FG at 3 years post partum delivered infants with reduced birth weight. Breastfeeding up to 6 months correlated with lower FG at 4 and 10 years post partum. A positive correlation between BMI and FG at 10 years after delivery (P = .03) was observed, particularly in overweight/obese patients requiring higher CAB doses. Patients with RH who had to restart CAB showed shorter breastfeeding duration and higher FG at 2 years post partum.

CONCLUSION

Low PRL levels before pregnancy may be detrimental to FG during pregnancy. CAB duration and dose may influence long-term glucose tolerance, besides family history and BMI. Preconception metabolic management should be recommended to reduce the risk of gestational and type 2 diabetes mellitus.

The research trend of hyperprolactinemia from 2011 to 2023 was analyzed by bibliometrics

The objective of this study is to conduct a bibliometric analysis of research trends in hyperprolactinemia from 2011 to 2023. This analysis aims to provide researchers with insights into the current hotspots and frontiers related to hyperprolactinemia. It is worth noting that there are currently no existing reports on bibliometric analyses of hyperprolactinemia. The Social Science Citation Index (SSCI) and Science Citation Index Expanded (SCIE) databases of the Web of Science Core Collection were systematically searched for "articles" and "review articles" related to the topic of hyperprolactinemia from 2011 to 2023. VOSviewer was employed to conduct bibliometric analysis, aiming to analyze the research trends in hyperprolactinemia over the past 13 years. A total of 1865 eligible articles were retrieved, with contributions from 9544 scholars representing 83 countries in the field of research. The United States had the highest number of publications, followed by China. The keywords were categorized into six clusters: (1) etiology of hyperprolactinemia and other related endocrine and metabolic diseases. (2) Hyperprolactinemia and mental illness. (3) Diagnosis and management of hyperprolactinemia. (4) Treatment of hyperprolactinemia and prolactinoma. (5) Detection of macroprolactin and macroprolactinemia. (6) Symptoms of male hyperprolactinemia. Over the past 13 years, there has been a consistent and slightly increasing trend in the number of research papers focusing on hyperprolactinemia. The primary areas of research focus are centered around the diagnosis and treatment of hyperprolactinemia caused by antipsychotic drugs or prolactinoma.

Exploring the association of serum prolactin with serum glucose levels and clinical findings in a cohort of patients with early rheumatoid arthritis

BACKGROUND

In the context of rheumatoid arthritis and its systemic inflammatory implications, there is an increasing interest in investigating the role of prolactin in the clinical and metabolic aspects of the disease. This study aimed to explore the potential links between serum prolactin levels, serum glucose levels, and the clinical manifestations of arthritis.

METHODS

This exploratory, cross-sectional, observational study focused on women diagnosed with rheumatoid arthritis. The research involved assessing prolactin and blood glucose concentrations, alongside specific clinical traits such as disease-related inflammation, morning stiffness, and fatigue intensity. The presence of changes in serum prolactin (PRL) was initially compared among the groups based on disease activity intensity. Using a multinomial regression analysis, the study analyzed the impact of predetermined clinical and metabolic factors on various categories of prolactin concentration.

RESULTS

Out of the 72 participants included in the study, hyperprolactinemia was detected in 9.1% of the sample. No differences in serum PRL were identified among the evaluated groups based on disease activity. Following multivariate analysis, no statistically significant differences were identified for the outcomes of inflammatory activity and morning stiffness within each PRL category when compared to the reference category for PRL. There was no increased likelihood of encountering blood glucose levels below 100 mg/dl among individuals with higher prolactin concentrations compared to those in the lowest prolactin category (OR 5.43, 95% CI 0.51-58.28). The presence of clinically significant fatigue revealed a higher likelihood of encountering this outcome among patients with intermediate PRL values (prolactin categories 7.76-10.35 with OR 5.18, 95% CI 1.01-26.38 and 10.36-15.29 with OR 6.25, 95% CI 1.2-32.51) when compared to the reference category.

CONCLUSIONS

The study found no discernible correlation between prolactin concentrations and worse scores for inflammatory activity of the disease, nor between prolactin concentrations and serum glucose levels. The findings regarding fatigue should be approached with caution given the exploratory nature of this study.

Autoimmune Thyroiditis Mitigates the Effect of Metformin on Plasma Prolactin Concentration in Men with Drug-Induced Hyperprolactinemia

Metformin inhibits the secretory function of overactive anterior pituitary cells, including lactotropes. In women of childbearing age, this effect was absent if they had coexisting autoimmune (Hashimoto) thyroiditis. The current study was aimed at investigating whether autoimmune thyroiditis modulates the impact of metformin on the plasma prolactin concentration in men. This prospective cohort study included two groups of middle-aged or elderly men with drug-induced hyperprolactinemia, namely subjects with concomitant Hashimoto thyroiditis (group A) and subjects with normal thyroid function (group B), who were matched for baseline prolactin concentration and insulin sensitivity. Titers of thyroid peroxidase and thyroglobulin antibodies, levels of C-reactive protein, markers of glucose homeostasis, concentrations of pituitary hormones (prolactin, thyrotropin, gonadotropins, and adrenocorticotropic hormone), free thyroxine, free triiodothyronine, testosterone, and insulin growth factor-1 were measured before and six months after treatment with metformin. Both study groups differed in titers of both antibodies and concentrations of C-reactive protein. The drug reduced the total and monomeric prolactin concentration only in group B, and the impact on prolactin correlated with the improvement in insulin sensitivity and systemic inflammation. There were no differences between the follow-up and baseline levels of the remaining hormones. The results allow us to conclude that autoimmune thyroiditis mitigates the impact of metformin on prolactin secretion in men.

Prolactin effects on the pathogenesis of diabetes mellitus

BACKGROUND

Prolactin (PRL) is a pituitary hormone promoting lactation in response to the suckling reflex. Beyond its well-known effects, novel tissue-specific and metabolic functions of PRL are emerging.

AIMS

To dissect PRL as a critical mediator of whole-body gluco-insulinemic sensitivity.

METHODS

PubMed-based search with the following terms 'prolactin', 'glucose metabolism', 'type 2 diabetes mellitus', 'type 1 diabetes mellitus', 'gestational diabetes mellitus' was performed.

DISCUSSION

The identification of the PRL-glucose metabolism network poses the basis for unprecedented avenues of research in the pathogenesis of diabetes mellitus type 1 or 2, as well as of gestational diabetes. In this regard, it is of timely relevance to define properly the homeostatic PRL serum levels since glucose metabolism could be influenced by the circulating amount of the hormone.

RESULTS

This review underscores the basic mechanisms of regulation of pancreatic β-cell functions by PRL and provides a revision of articles which have investigated the connection between PRL unbalancing and diabetes mellitus. Future studies are needed to elucidate the burden and the role of PRL in the regulation of glucose metabolism and determine the specific PRL threshold that may impact the management of diabetes.

CONCLUSION

A careful evaluation and context-driven interpretation of PRL levels (e.g., pregnancy, PRL-secreting pituitary adenomas, drug-related hyper- and hypoprolactinemia) could be critical for the correct screening and management of glucometabolic disorders, such as type 1 or 2 as well as gestational diabetes mellitus.

Pre-and post-surgical non-functional pituitary adenomas and their relationship with high levels of serum glucose

OBJECTIVES

This clinical, analytical, retro-prospective, auto-controlled, not randomized, and not blinded study, aimed to investigate the association of changes in the serum glucose levels with the pre-and-post changes in the size tumor in mm3 in the Non-Functional pituitary adenomas.

METHODS

Pre-and post-surgical MRI, as well as the measurements in the serum glucose levels and immunohistochemical techniques were performed in all the patients in the study, with a mean followed-up until 208.57 days. A comparison was made between the reductions in tumor size of hormonally active pituitary adenomas (HSPAs) vs NFPAs.

RESULTS

Seventy-four patients were included in this study, of whom, 46 were NFPAs. The decrease in the NFPAs tumor size after surgery was statistically significant (P ≤ 0.0001). The Mean of the differences of both type of tumors in mm3 were -9552 ± 10287. Pre-surgery, the mean of the HSPAs were 8.923 ± 2.078; and the NFPAs were 14.161 ± 1.912. The differences in the tumor size were statistically significant (p = 0.039). Post-surgical, the mean of the HSPAs were 2.079 ± 971, with a (p = 0.14): and the NFPAs were 4.609 ± 1.205. After surgery of the NFPAs, most of the patients-maintained serum levels ≤ 100 mg/dL, with a statistical significance (P ≤ 0.0003).

CONCLUSION

This study demonstrates for the first time the correlation between the presence of pre-and post- surgical changes in the NFPAs, with modifications in the levels of serum glucose, and the comparison, pre- and post-surgical between the tumor size of HSPAs and NFPAs.

Dopamine D2 receptor antagonist counteracts hyperglycemia and insulin resistance in diet-induced obese male mice

Obesity leads to insulin resistance (IR) and type 2 diabetes. In humans, low levels of the hormone prolactin (PRL) correlate with IR, adipose tissue (AT) dysfunction, and increased prevalence of T2D. In obese rats, PRL treatment promotes insulin sensitivity and reduces visceral AT adipocyte hypertrophy. Here, we tested whether elevating PRL levels with the prokinetic and antipsychotic drug sulpiride, an antagonist of dopamine D2 receptors, improves metabolism in high fat diet (HFD)-induced obese male mice. Sulpiride treatment (30 days) reduced hyperglycemia, IR, and the serum and pancreatic levels of triglycerides in obese mice, reduced visceral and subcutaneous AT adipocyte hypertrophy, normalized markers of visceral AT function (PRL receptor, Glut4, insulin receptor and Hif-1α), and increased glycogen stores in skeletal muscle. However, the effects of sulpiride reducing hyperglycemia were also observed in obese prolactin receptor null mice. We conclude that sulpiride reduces obesity-induced hyperglycemia by mechanisms that are independent of prolactin/prolactin receptor activity. These findings support the therapeutic potential of sulpiride against metabolic dysfunction in obesity.

Strategy for Identifying a Robust Metabolomic Signature Reveals the Altered Lipid Metabolism in Pituitary Adenoma

Despite the well-established connection between systematic metabolic abnormalities and the pathophysiology of pituitary adenoma (PA), current metabolomic studies have reported an extremely limited number of metabolites associated with PA. Moreover, there was very little consistency in the identified metabolite signatures, resulting in a lack of robust metabolic biomarkers for the diagnosis and treatment of PA. Herein, we performed a global untargeted plasma metabolomic profiling on PA and identified a highly robust metabolomic signature based on a strategy. Specifically, this strategy is unique in (1) integrating repeated random sampling and a consensus evaluation-based feature selection algorithm and (2) evaluating the consistency of metabolomic signatures among different sample groups. This strategy demonstrated superior robustness and stronger discriminative ability compared with that of other feature selection methods including Student's t-test, partial least-squares-discriminant analysis, support vector machine recursive feature elimination, and random forest recursive feature elimination. More importantly, a highly robust metabolomic signature comprising 45 PA-specific differential metabolites was identified. Moreover, metabolite set enrichment analysis of these potential metabolic biomarkers revealed altered lipid metabolism in PA. In conclusion, our findings contribute to a better understanding of the metabolic changes in PA and may have implications for the development of diagnostic and therapeutic approaches targeting lipid metabolism in PA. We believe that the proposed strategy serves as a valuable tool for screening robust, discriminating metabolic features in the field of metabolomics.

Metabolic Syndrome Components in Patients with Pituitary Adenoma

Pituitary adenomas are benign tumors of the anterior portion of the pituitary gland (adenohypophysis), representing the 25% of all the tumor alterations. Pituitary adenomas are classified by the type of hormone secreted, cellularity, size, and structural alterations by the hormonal segregation. The diagnosis consists on the histopathological identification of cell types and the image-guided by magnetic resonance or tomography; the treatment can be both pharmacological and surgical. Metabolic Syndrome is the set of clinical conditions that increase the risk of cardiovascular diseases with an estimated prevalence of 25% worldwide. The alterations of metabolic syndrome are obesity, hypertension, dyslipidemia, insulin resistance, and diabetes mellitus type II. Pituitary adenomas and metabolic syndrome have an important relationship, hormone-secreting by pituitary adenomas affects a myriad of signaling pathways, which allows a favorable environment for the appearance of the metabolic syndrome. Moreover, patients with pituitary adenomas are shown to have an improvement in metabolic parameters after the medical/surgical treatment. The objective of this review is to explore the possible mechanisms through which PAs contributes to MetSx.

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

PURPOSE

Data on the role of prolactin (PRL) in the physiologic range in the female sexual response are scanty. We aimed at investigating the association between PRL and sexual function as assessed by the Female Sexual Function Index (FSFI). We explored the presence of a cut-off level of PRL able to identify Hypoactive Sexual Desire Disorder (HSDD).

METHODS

277 pre- and post-menopausal women consulting for Female Sexual Dysfunction (FSD) and sexually active were enrolled in an observational, retrospective study. 42 women were used as no-FSD controls. A clinical, biochemical and psychosexual evaluation was performed. The main outcome measures were: FSFI, Female Sexual Distress Scale-Revised, Middlesex Hospital Questionnaire and Sexual excitation/sexual inhibition scale (SIS/SES).

RESULTS

Normo-PRL FSD women (n = 264) showed lower FSFI Desire score than controls (n = 42), and higher than hyper-PRL FSD women (n = 13). These differences emerged both in pre-menopausal and post-menopausal subjects. In the normo-PRL FSD group, those with PRL in the higher quintile reported higher FSFI Desire scores than those with PRL in the lowest quintile. Women with HSDD presented a lower PRL level than those without (p = 0.032). A ROC curve analysis for PRL showed an accuracy of 0.610 ± 0.044 (p = 0.014) in predicting HSDD. With a threshold of < 9.83 μg/L, sensitivity and specificity for HSDD were 63% and 56%, respectively. Subjects with PRL < 9.83 μg/L also reported lower sexual inhibition (p = 0.006) and lower cortisol levels (p = 0.003) than those with PRL >  = 9.83 μg/L.

CONCLUSIONS

Hyper-PRL is associated with low desire; however, among normo-PRL FSD women, those with the lowest levels demonstrated a poorer desire than those with the highest levels. PRL < 9.83 μg/L predicted HSDD and a lower sexual inhibitory trait.

Association of prolactin with all-cause and cardiovascular mortality among patients with type 2 diabetes: a real-world study

AIMS

The association between prolactin and mortality has been less studied, and findings were inconsistent among different populations. We aimed to investigate the association between serum prolactin (PRL) and mortality among patients with type 2 diabetes.

METHODS AND RESULTS

We performed a retrospective cohort study of 10 907 patients with at least 2 prolactin measurements within 2 years since their first inpatient diagnosis of type 2 diabetes. Baseline and mean values of serum PRL were used as exposures. A multivariable-adjusted Cox proportional hazards model was used to estimate the association between PRL and mortality. During a mean follow-up of 5.34 years, 863 patients died, of whom 274 were due to cardiovascular events. Multivariable-adjusted hazard ratios (aHRs) based on different levels of baseline PRL (<100, 100-199, 200-299, and ≥300 mIU/L) were 1.00, 1.10 [95% confidence interval (CI), 0.90-1.36], 1.35 (95% CI 1.11-1.67), and 1.49 (95% CI 1.18-1.84) for all-cause mortality and 1.00, 1.24 (95% CI 0.86-1.81), 1.71 (95% CI 1.14-2.62), and 2.42 (95% CI 1.55-3.78) for cardiovascular mortality, respectively. Positive associations were also found when we used the mean values of PRL as the exposure. These associations were consistent among patients of different baseline characteristics. Further sensitivity analyses excluding patients with subclinical or clinical hypothyroidism at baseline and who died within the first 6 months since baseline demonstrated similar results.

CONCLUSIONS

A positive association between baseline PRL and mortality was observed among patients with type 2 diabetes. Prolactin may be considered a potential biomarker of mortality among patients with type 2 diabetes.

The Effect of Metformin on Plasma Prolactin Levels in Young Women with Autoimmune Thyroiditis

Metformin decreases elevated prolactin levels, which are frequently found in patients with thyroid disorders. The aim of this study was to investigate whether thyroid autoimmunity modulates the impact of metformin on lactotrope secretory function. This study compared two matched groups of young women with prediabetes and mild-to-moderate prolactin excess: 28 subjects with coexisting euthyroid autoimmune thyroiditis (group 1) and 28 individuals without thyroid disorders (group 2), treated for six months with metformin (3 g daily). Thyroid antibody titers, glucose homeostasis markers, prolactin, thyrotropin, free thyroid hormones, FSH, LH, ACTH, IGF-1 and hsCRP were assessed at the beginning and at the end of the study. At entry, the study groups differed in antibody titers and hsCRP levels. Although the improvement in glucose homeostasis and the decrease in hsCRP levels were observed in both study groups, they were more pronounced in group 2. Only in group 2 did metformin reduce circulating prolactin levels (both total and monomeric). Prolactin-lowering properties of metformin positively correlated with baseline prolactin levels, baseline antibody titers (in group 1) and with the degree of reduction in hsCRP levels. The obtained results suggest that autoimmune thyroiditis may attenuate the impact of metformin on lactotrope secretory function.

Vitamin D Status Determines Cardiometabolic Effects of Cabergoline in Women with Elevated Prolactin Levels: A Pilot Study

Both hyperprolactinemia and vitamin D deficiency appear to be associated with increased cardiometabolic risk. This study aimed to determine whether vitamin D status influences the cardiometabolic effects of cabergoline. The study included three matched groups of women with mild to moderate hyperprolactinemia: vitamin D-naive subjects with vitamin D insufficiency (group A), women with vitamin D deficiency/insufficiency successfully treated with vitamin D (group B), and vitamin D-naive individuals with normal vitamin D status (group C). Plasma prolactin, 25-hydroxyvitamin D, estradiol, glucose homeostasis markers, lipids, high-sensitivity C-reactive protein (hsCRP), fibrinogen, homocysteine, and uric acid, as well as the urinary albumin-to-creatinine ratio (UACR), were measured at study entry and after four months of cabergoline treatment. Although cabergoline reduced prolactin levels and increased estradiol levels in all study groups, the effect on prolactin was more pronounced in groups B and C compared to group A. In groups B and C, the drug enhanced glucose homeostasis, increased HDL-cholesterol, and decreased triglycerides, hsCRP, fibrinogen, homocysteine, uric acid, and UACR. In group A, only insulin resistance, hsCRP, and homocysteine were reduced by cabergoline. The effects on insulin sensitivity, HDL-cholesterol, triglycerides, hsCRP, fibrinogen, homocysteine, uric acid, and UACR were proportional to the decrease in prolactin and baseline levels of 25-hydroxyvitamin D. The obtained results suggest that vitamin D status determines cabergoline's cardiometabolic effects.

Cardiometabolic Effects of Cabergoline and Combined Oral Contraceptive Pills in Young Women with Hyperprolactinemia: A Pilot Study

Although dopaminergic agents are the drugs of choice in treatment of prolactin excess, women who cannot be treated with these agents are recommended to receive estrogen preparations. The aim of this study was to compare cardiometabolic effects of both treatment options. The study population included three groups of young women. Subjects with mild-to-moderate hyperprolactinemia received either low-dose cabergoline or oral combined contraceptives (ethinyl estradiol plus desogestrel), while normoprolactinemic women were drug-naive. Plasma prolactin, glucose homeostasis markers, lipids, circulating levels of uric acid, high-sensitivity C-reactive protein (hsCRP), fibrinogen and homocysteine, and the urinary albumin-to-creatinine ratio (UACR) were assessed at entry and six months later. Hyperprolactinemic women differed from normoprolactinemic ones in glucose homeostasis markers, high-density lipoprotein (HDL)-cholesterol, triglycerides, uric acid, hsCRP, fibrinogen, homocysteine and UACR. Cabergoline decreased total and monomeric prolactin levels, which was accompanied by normalization of glucose, insulin sensitivity, glycated hemoglobin, HDL-cholesterol, triglycerides, uric acid, hsCRP, fibrinogen, homocysteine and UACR. Despite a neutral effect on prolactin levels, combined contraceptives worsened insulin sensitivity and increased triglycerides, hsCRP, fibrinogen and UACR. At follow-up, cabergoline-treated women were characterized by a better cardiometabolic profile than women receiving ethinyl estradiol plus desogestrel. Our findings suggest that only cabergoline reduces cardiometabolic risk in young women with hyperprolactinemia.

Effects of Anterior Pituitary Adenomas' Hormones on Glucose Metabolism and Its Clinical Implications

Pituitary adenomas have recently become more common and their incidence is increasing yearly. Functional pituitary tumors commonly secrete prolactin, growth hormones, and adrenocorticotropic hormones, which cause diseases such as prolactinoma, acromegaly, and Cushing's disease, but rarely secrete luteinizing, follicle-stimulating, thyroid-stimulating, and melanocyte-stimulating hormones. In addition to the typical clinical manifestations of functional pituitary tumors caused by excessive hormone levels, some pituitary tumors are also accompanied by abnormal glucose metabolism. The effects of these seven hormones on glucose metabolism are important for the treatment of diabetes secondary to pituitary tumors. This review focuses on the effects of hormones on glucose metabolism, providing important clues for the diagnosis and treatment of related diseases.

Gene Networks of Hyperglycemia, Diabetic Complications, and Human Proteins Targeted by SARS-CoV-2: What Is the Molecular Basis for Comorbidity?

People with diabetes are more likely to have severe COVID-19 compared to the general population. Moreover, diabetes and COVID-19 demonstrate a certain parallelism in the mechanisms and organ damage. In this work, we applied bioinformatics analysis of associative molecular networks to identify key molecules and pathophysiological processes that determine SARS-CoV-2-induced disorders in patients with diabetes. Using text-mining-based approaches and ANDSystem as a bioinformatics tool, we reconstructed and matched networks related to hyperglycemia, diabetic complications, insulin resistance, and beta cell dysfunction with networks of SARS-CoV-2-targeted proteins. The latter included SARS-CoV-2 entry receptors (ACE2 and DPP4), SARS-CoV-2 entry associated proteases (TMPRSS2, CTSB, and CTSL), and 332 human intracellular proteins interacting with SARS-CoV-2. A number of genes/proteins targeted by SARS-CoV-2 (ACE2, BRD2, COMT, CTSB, CTSL, DNMT1, DPP4, ERP44, F2RL1, GDF15, GPX1, HDAC2, HMOX1, HYOU1, IDE, LOX, NUTF2, PCNT, PLAT, RAB10, RHOA, SCARB1, and SELENOS) were found in the networks of vascular diabetic complications and insulin resistance. According to the Gene Ontology enrichment analysis, the defined molecules are involved in the response to hypoxia, reactive oxygen species metabolism, immune and inflammatory response, regulation of angiogenesis, platelet degranulation, and other processes. The results expand the understanding of the molecular basis of diabetes and COVID-19 comorbidity.

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.

J-Shaped Relationship Between Serum Prolactin and Metabolic-Associated Fatty Liver Disease in Female Patients With Type 2 Diabetes

BACKGROUND

Metabolic-associated fatty liver disease (MAFLD) has become a worldwide epidemic. Prolactin (PRL), a pituitary hormone, has been linked to MAFLD. As a result, we set out to look into the relationship between serum PRL and the risk of MAFLD in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 724 adults with T2DM were enrolled and categorized as MAFLD and non-MAFLD groups. Anthropometric data, biochemical parameters, and serum PRL levels were collected. Liver steatosis and fibrosis were assessed using FibroScan. Patients were stratified into normal PRL (NP) and high PRL (HP) groups and divided into four groups based on serum PRL quartiles. Multivariate logistic regression analysis was performed to evaluate the association between serum PRL and MAFLD risk.

RESULTS

Female but not male patients with MAFLD, liver steatosis, and fibrosis had significantly lower PRL levels in the NP group but higher PRL levels in the HP group than their counterparts. The proportions of MAFLD, liver steatosis, and fibrosis were significantly decreased in the NP group but increased in the HP group across the PRL quartiles in females but not in males. After multivariate adjustment, the adjusted ORs (AORs) and 95% CI for MAFLD among females were 18.165 (3.425-96.336), 1.784 (0.658-5.002), 1.744 (0.608-4.832), and 1.00 (reference) in the NP group (Q1-Q4, P-trend < 0.001) and 1.00 (reference), 11.098 (1.819-110.356), 15.225 (1.996-116.112), and 18.211 (2.579-128.568) in the HP group (Q1-Q4, P-trend = 0.020). Such associations were also found between serum PRL and liver fibrosis in females but not in males.

CONCLUSION

We observed a J-shaped association between serum PRL and the risk of MAFLD and liver fibrosis in females but not in males with T2DM, indicating that PRL may be relevant to MAFLD and its progression in a gender-specific manner.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registry, number ChiCTR-OCS-12002381.

Metabolic effects of prolactin

Over the last years, the metabolic role of PRL has emerged. PRL excess is known to promote weight gain, obesity, metabolic syndrome, and impairment in gluco-insulinemic and lipid profiles, likely due to the suppression of physiologic dopaminergic tone. Prolactin receptors and dopamine receptors type 2 have been demonstrated to be expressed on both human pancreatic β- cell and adipocytes, supporting a key role of prolactin and dopamine in peripheral metabolic regulation. Medical treatment with the dopamine agonists bromocriptine and cabergoline has been demonstrated to decrease the prevalence of metabolic syndrome and obesity, and significantly improve gluco-insulinemic and lipid profiles. In hyperprolactinemic men with concomitant hypogonadism, correction of hyperprolactinaemia and testosterone replacement has been proven to restore metabolic impairment. In turn, low prolactin levels have also been demonstrated to exert a detrimental effect on weight gain, glucose and lipid metabolism, thus leading to an increased prevalence of metabolic syndrome. Therefore, PRL values ranging from 25 to 100 mg/L, in absence of other recognizable pathological causes, have been proposed to represent a physiological response to the request for an increase in metabolic activity, and nowadays classify the so-called HomeoFIT- PRL as a promoter of metabolic homeostasis. The current review focuses mainly on the effects of hyperprolactinemia and its control by medical treatment with DAs on the modulation of food intake, body weight, gluco-insulinemic and lipid profile. Furthermore, it provides the latest knowledge about the metabolic impact of hypoprolactinemia.

Meal Timing and Glycemic Control during Pregnancy-Is There a Link?

Hyperglycemia during pregnancy and gestational diabetes mellitus (GDM) constitute an important public health problem due to their prevalence and long-term health consequences both for the mother and offspring. Results from studies in rodents and some clinical investigations suggest that meal time manipulation may be a potential lifestyle approach against conditions involving perturbations in glucose homeostasis (e.g., hyperglycemia, insulin resistance, diabetes, etc.). The purpose of this review is to summarize and critically evaluate the current literature on the role of meal timing and daily nutrient distribution on glycemic control during pregnancy. Only a small number of mostly observational studies have assessed the role of meal timing in glucose homeostasis during pregnancy. Food consumption earlier in the day and short-term fasting with adequate nutrient intake may improve glycemic control during the second and third trimester of gestation. Considering that the field of chrononutrition is still in its infancy and many questions remain unanswered, future prospective and carefully designed studies are needed to better understand the role of meal timing in metabolic homeostasis and maternal and fetal health outcomes during pregnancy.

Hyperprolactinemia after menopause: Diagnosis and management

Most prolactinomas are diagnosed in women of reproductive age and are generally microadenomas. Prolactinomas diagnosed in postmenopausal women are less common and are not usually associated with the typical syndrome induced by prolactin excess, including infertility and oligo-amenorrhea. This implies that the diagnosis of prolactinomas after menopause may be delayed and require greater clinical effort. Limited data are available on the management and prognosis of prolactinomas in postmenopausal women. However, the physiologic decline of prolactin levels during menopause and the lack of fertility concerns, which represent specific indications for medical treatment with dopamine agonists, might require a careful reassessment of therapeutic management in such patients. Postmenopausal women with microprolactinoma may be successfully withdrawn from medical therapy with dopamine agonists, whereas in those with macroprolactinomas greater caution is advisable before dopamine agonists are discontinued, considering the potential, although rare, tumor enlargement. This review focuses on the diagnostic challenges and therapeutic management of prolactinomas in postmenopausal women.

Current and emerging gluconeogenesis inhibitors for the treatment of Type 2 diabetes

INTRODUCTION

In the last several decades, fueled by gene knockout and knockdown techniques, there has been substantial progress in detailing the pathways of gluconeogenesis. A host of molecules have been identified as potential targets for therapeutic intervention. A number of hormones, enzymes and transcription factors participate in gluconeogenesis. Many new agents have come into use to treat diabetes and several of these are in development to suppress gluconeogenesis.

AREAS COVERED

Herein, the author reviews agents that have been discovered and/or are in development, which control excess gluconeogenesis. The author has used multiple sources including PubMed, the preprint servers MedRxIv, BioRxIv, Research Gate, as well as Google Search and the database of the U.S. Patent and Trademarks Office to find appropriate literature.

EXPERT OPINION

It is now clear that lipid metabolism and hepatic lipogenesis play a major role in gluconeogenesis and resistance to insulin. Future efforts will focus on the duality of gluconeogenesis and adipose tissue metabolism. The exploration of therapeutic RNA agents will accelerate. The balance of clinical benefit and adverse effects will determine the future of new gluconeogenesis inhibitors.

Loss of growth hormone signaling in the mouse germline or in adulthood reduces islet mass and alters islet function with notable sex differences

In the endocrine pancreas, growth hormone (GH) is known to promote pancreatic islet growth and insulin secretion. In this study, we show that GH receptor (GHR) loss in the germline and in adulthood impacts islet mass in general but more profoundly in male mice. GHR knockout (GHRKO) mice have enhanced insulin sensitivity and low circulating insulin. We show that the total cross-sectional area of isolated islets (estimated islet mass) was reduced by 72% in male but by only 29% in female GHRKO mice compared with wild-type controls. Also, islets from GHRKO mice secreted ∼50% less glucose-stimulated insulin compared with size-matched islets from wild-type mice. We next used mice with a floxed Ghr gene to knock down the GHR in adult mice at 6 mo of age (6mGHRKO) and examined the impact on glucose and islet metabolism. By 12 mo of age, female 6mGHRKO mice had increased body fat and reduced islet mass but had no change in glucose tolerance or insulin sensitivity. However, male 6mGHRKO mice had nearly twice as much body fat, substantially reduced islet mass, and enhanced insulin sensitivity, but no change in glucose tolerance. Despite large losses in islet mass, glucose-stimulated insulin secretion from isolated islets was not significantly different between male 6mGHRKO and controls, whereas isolated islets from female 6mGHRKO mice showed increased glucose-stimulated insulin release. Our findings demonstrate the importance of GH to islet mass throughout life and that unique sex-specific adaptations to the loss of GH signaling allow mice to maintain normal glucose metabolism.NEW & NOTEWORTHY Growth hormone (GH) is important for more than just growth. GH helps to maintain pancreatic islet mass and insulin secretion throughout life. Sex-specific adaptations to the loss of GH signaling allow mice to maintain normal glucose regulation despite losing islet mass.

Berberine modulates crucial erectogenic biomolecules and alters histological architecture in penile tissues of diabetic rats

Berberine is an isoquinoline alkaloid, found in several plants. Diabetes induces erectile dysfunction (ED) via reduction in some hormones and enzymes implicated in sexual function. This study aimed to investigate the role of berberine on crucial biomolecules linked to penile function in diabetic rats. Sixty-three (63) adult male rats were used and distributed into nine groups (each = 7). Group I-IV normal rats administered with citrate buffer (pH 4.5), sildenafil citrate (SD, 5.0 mg/kg), 50 and 100 mg/kg of berberine, respectively, via oral gavage. Rats in groups V-IX were diabetic rat with ED treated with buffer, SD, 50 and 100 mg/kg of berberine, and acarbose (25 mg/kg ACA) respectively. The result revealed that histological architecture in penile tissues were altered in diabetic groups treated with berberine, sildenafil citrate and acarbose when compared to the diabetic control group. Treatment with berberine, increased testosterone, luteinizing hormone and follicle-stimulating hormone in diabetic rat with ED. Also, reduced prolactin level and acetylcholinesterase, angiotensin-1 converting enzyme, adenosine deaminase and arginase activities were observed in berberine treated diabetic rat with ED. Molecular docking analysis revealed that berberine had strong binding affinities for these enzymes. Thus, berberine could represent a potential therapeutic agent for diabetes-induced ED.

Adverse body composition and lipid parameters in patients with prolactinoma: a case-control study

BACKGROUND

Hyperprolactinaemia might cause adverse metabolic effects. The aim of our study was to compare parameters of body composition, glucose and lipid metabolism between untreated patients with prolactinoma and controls and to assess changes after initiation of cabergoline.

METHODS

Case-control study with a retrospectively analyzed follow-up in patients with prolactinoma after initiation of cabergoline therapy.

RESULTS

21 patients with prolactinoma (9 micro- and 12 macroprolactinomas; 7 females) and 30 controls were analyzed. Patients with prolactinoma had significantly higher BMI than controls; fat mass did not differ between groups. Only men - but not women - with prolactinoma had significantly higher fat mass at all six sites measured compared to controls. Levels of LDL (130 (107-147.5) vs. 94.5 (80-127.5) mg/dl, p < 0.001) were significantly higher, levels of HDL (56 ± 16.7 vs. 69.2 ± 14.6 mg/dl, p = 0.004) significantly lower than in controls. Fasting glucose, HOMA-IR, HbA1c, adiponectin, CRP, and homocysteine did not differ between groups. After a median of 10 weeks (IQR 7-18 weeks) after initiation of cabergoline, total (from 212.5 ± 36.2 to 196.9 ± 40.6 mg/dl, p = 0.018) and LDL cholesterol (130 (107-147.5) to 106.5 (94.3-148) mg/dl, p = 0.018) had significantly decreased. Analyzing men and women separately, this change occurred in men only.

CONCLUSIONS

Reasons for the association between prolactin and metabolic parameters include direct effects of prolactin on adipose tissue, hyperprolactinaemia-triggered hypogonadism and dopamine-agonist therapy per se. Altered lipid metabolism in patients with prolactinoma might imply an increased cardiovascular risk, highlighting the necessity to monitor metabolic parameters in these patients.

The Effect of Pituitary Gland Disorders on Glucose Metabolism: From Pathophysiology to Management

This review aims to explore, present, and discuss disorders of glucose metabolism implicated in pituitary gland diseases, the appropriate interventions, as well as the therapeutic challenges that may arise. Pituitary pathologies may dysregulate glucose homeostasis, as both the excess and deficiency of various pituitary hormones can affect glucose metabolism. Increased circulating levels of growth hormone, glucocorticoids or prolactin have been shown to mainly provoke hyperglycemic states, while hypopituitarism can be associated with both hyperglycemia and hypoglycemia. Addressing the primary cause of these disorders with the use of surgery, medical treatment or radiotherapy forms the cornerstone of current management strategies. Physicians should bear in mind that some such medications have an unfavorable effect on glucose metabolism too. When unsuccessful, or until the appropriate treatment of the underlying pituitary problem, the addition of established antidiabetic therapies might prove useful. Further studies aiming to discover more accurate and effective drug preparations in combination with optimal lifestyle management models will contribute to achieving a more successful glycemic control in these patients.

Effects of Pituitary Surgery and High-Dose Cabergoline Therapy on Metabolic Profile in Patients With Prolactinoma Resistant to Conventional Cabergoline Treatment

OBJECTIVE

Control of prolactin excess is associated with the improvement in gluco-insulinemic and lipid profile. The current study aimed at investigating the effects of pituitary surgery and medical therapy with high dose cabergoline (≥2mg/week) on metabolic profile in patients with prolactinoma resistant to cabergoline conventional doses (<2mg/week).

DESIGN

Thirty-four patients (22 men, 12 women, aged 33.9 ± 12.5 years) with prolactinoma (4 microadenomas and 30 macroadenomas) were included in the present study. Among them 17 (50%) received pituitary surgery (PS, Group1) and 17 (50%) medical therapy with high dose cabergoline (Group 2).

METHODS

In the whole patient cohort, anthropometric (weight, BMI) and biochemical (fasting glucose and insulin, triglycerides, total, HDL and LDL-cholesterol, HOMA-IR, HOMA-β and ISI0) parameters were evaluated before and within 12 months after treatment.

RESULTS

In Group 1, prolactin (p=0.002), total cholesterol (p=0.012), and triglycerides (p=0.030) significantly decreased after pituitary surgery compared to the baseline. Prolactin significantly correlated with fasting glucose (r=0.056, p=0.025). In Group 2, fasting insulin (p=0.033), HOMA-β (p=0.011) and ISI0 (p=0.011) significantly improved compared to baseline. Postoperative cabergoline dose significantly correlated with Δfasting glucose (r=-0.556, p=0.039) and ΔLDL cholesterol (r=- 0.521, p=0.046), and was the best predictor of ΔLDL cholesterol (r^{2 =} 0.59, p=0.002) in Group 1.

CONCLUSIONS

The rapid decrease in PRL levels induced by PS might improve lipid metabolism, whereas HD-CAB might exert a beneficial impact on both insulin secretion and peripheral sensitivity, thus inducing a global metabolic improvement.

Genomic and transcriptomic analysis of pituitary adenomas reveals the impacts of copy number variations on gene expression and clinical prognosis among prolactin-secreting subtype

Pituitary adenomas (PAs) are slow growing and benign primary intracranial tumors that often cause occupying effects or endocrine symptoms. PAs can be classified into various subtypes according to hormone secretion. Although widespread transcriptional alterations that cause aberrant hormone secretion have been characterized, the impact of genomic variations on transcriptional alterations is unclear due to the rare occurrence of single-nucleotide variations in PA. In this study, we performed whole-genome sequencing (WGS) on 76 PA samples across three clinical subtypes (PRL-PAs; GH-PAs, and NFPAs); transcriptome sequencing (RNA-seq) of 54 samples across these subtypes was also conducted. Nine normal pituitary tissues were used as controls. Common and subtype-specific transcriptional alterations in PAs were identified. Strikingly, widespread genomic copy number amplifications were discovered for PRL-PAs, which are causally involved in transcriptomic changes in this subtype. Moreover, we found that the high copy number variations (CNVs) in PRL-PA cause increased prolactin production, drug resistance and proliferative capacity, potentially through key genes with copy number amplification and transcriptional activation, such as BCAT1. This study provides insight into how genomic CNVs affect the transcriptome and clinical outcomes of PRL-PA and sheds light on the development of potential therapeutics for aberrantly activated targets.

Metabolic functions of prolactin: Physiological and pathological aspects

Prolactin is named after its vital role of promoting milk production during lactation, although it has been implicated in multiple functions within the body, including metabolism and energy homeostasis. Prolactin has been hypothesised to play a key role in driving many of the adaptations of the maternal body to allow the mother to meet the physiological demands of both pregnancy and lactation, including the high energetic demands of the growing foetus followed by milk production to support the offspring after birth. Prolactin receptors are found in many tissues involved in metabolism and food intake, such as the pancreas, liver, hypothalamus, small intestine and adipose tissue. We review the literature examining the effects of prolactin in these various tissues and how they relate to changes in function in physiological states of high prolactin, such as pregnancy and lactation, and in pathological states of hyperprolactinaemia in the adult. In many cases, whether prolactin promotes healthy metabolism or leads to dysregulation of metabolic functions is highly dependent on the situation. Overall, although prolactin may not play a major role in regulating metabolism and body weight outside of pregnancy and lactation, it definitely has the ability to contribute to metabolic function.

Influence of the use of atypical antipsychotics in metabolic syndrome

OBJECTIVES

To describe the possible relationship between the use of antipsychotic drugs and the presence of metabolic syndrome. Other objectives are to list the main side effects of antipsychotic treatment, and to determine if there is any pharmacological treatment that can contribute towards counteracting metabolic syndrome.

MATERIAL AND METHOD

A narrative bibliographic review was carried out of the following databases: PubMed, Cochrane, CINAHL, IBECS, LILACS and HealthCare. Preference in the selection process was given to clinical trials and systematic review articles or review articles and some articles that were considered relevant because of their content. The time period was limited to between January 2014 and November 2019. The languages were English and Spanish. Repeated articles and those that were not related to the objectives were rejected. The search criteria were: "antipsychotic AND metabolic syndrome"; "schizophrenia AND metabolic syndrome"; "bipolar disorder AND metabolic syndrome"; "metabolic syndrome AND suicide NOT disorder"; "metabolic syndrome AND prisons"; "metabolic syndrome AND prolactin".

RESULTS

24 articles were selected out of the 510 that were consulted. The relationship between atypical antipsychotics and metabolic syndrome was evident. Other anticholinergic, antidopaminergic effects, extrapyramidal syndromes, neuroleptic malignant syndrome, hypotension, arrhythmias, sedation, hypovitaminosis D, increased prolactin, sexual dysfunction, sleep disturbances, etc. are also highlighted. Pharmacological associations with other drugs were also found.

DISCUSSION

There is a relationship between the use of atypical antipsychotics and weight gain, lipid disorders, glucose and high blood pressure. There are some associated drugs that decrease some symptoms (ranitidine, topiramate, metformin, melatonin, modafinil). Patients taking this type of medication should be monitored and encouraged to lead healthy lifestyles.

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.

The role of prolactin in co-ordinating fertility and metabolic adaptations during reproduction

Mammalian pregnancy and lactation is accompanied by a period of infertility that takes place in the midst of a sustained increase in food intake. Indeed, successful reproduction in females is dependent on co-ordination of the distinct systems that regulate reproduction and metabolism. Rather than arising from different mechanisms during pregnancy and lactation, we propose that elevations in lactogenic hormones (predominant among these being prolactin and the placental lactogens), are ideally placed to influence both of these systems at the appropriate time. We review the literature examining the impacts of lactogens on fertility and energy homeostasis in the virgin state, during pregnancy and lactation and potential long-term impacts of reproductive experience. Taken together, the literature indicates that duration and pattern of lactogen exposure is a vital factor in the ability of these hormones to alter reproduction and food intake. Transient increases in prolactin, as typically seen in healthy virgin females and males, are unable to exert lasting impacts. Importantly, both suppression of fertility and increased food intake are only observed following exposure to chronically-elevated levels of lactogens. Physiologically, the only time this pattern of lactogenic secretion is maintained in the healthy female is during pregnancy and lactation, when co-ordination between these regulatory systems emerges. This article is part of the special issue on 'Neuropeptides'.