Pitfalls in the Diagnostic Evaluation of Hyperprolactinemia

Screening with Metoclopramide Test to Reduce Unnecessary Pituitary Magnetic Resonance Studies in Moderate Hyperprolactinemia

BACKGROUND

In prolactinoma diagnosis, current guidelines recommend prolactin (PRL) assessment, considering values exceeding 200 ng/mL highly suggestive of prolactinoma. However, subtler hyperprolactinemia is more common, and to rule out potential prolactinomas, pituitary resonance magnetic imaging (MRI) studies are necessary. These present limitations in terms of availability, costs, and delays in diagnosis. We aimed to evaluate the screening utility of the metoclopramide (MCP) test in identifying patients with moderate hyperprolactinemia for whom MRI studies might be unnecessary.

METHODS

We retrospectively selected patients with moderate hyperprolactinemia, with an MCP test and a pituitary MRI within the same assistance, and with no interfering pharmacological treatment. Increases in PRL (ΔPRLMax) and thyrotropin (ΔTSHMax) after MCP infusion were compared according to MRI findings: patients with microadenoma (<10 mm; n = 23), with macroadenoma (≥10 mm; n = 5), or without adenoma (n = 39).

RESULTS

ΔPRLMax exceeds baseline PRL capability to identify patients with an adenoma (area under the curve = 0.872 vs 0.776). ΔPRLMax below 220% identifies 100% of these patients with 71% of specificity. This screening would have avoided 42% of MRI, resulting in a cost savings of 34%. Analysis of ΔTSHMax only slightly increased specificity when considered as a secondary criterion. Test duration can be shortened to 30 min without compromising its screening capability.

CONCLUSIONS

A short MCP test is a useful and cost-effective screening tool to avoid unnecessary MRI. Its simplicity allows its performance in almost any clinical facility to easily rule out prolactinoma in an important percentage of patients, something of upmost importance especially in regions where MRI facilities or their access are limited.

Prolactin in sleep and EEG regulation: New mechanisms and sleep-related brain targets complement classical data

The role of prolactin in sleep regulation has been the subject of extensive research over the past 50 years, resulting in the identification of multiple, disparate functions for the hormone. Prolactin demonstrated a characteristic circadian release pattern with elevation during dark and diminution during light. High prolactin levels were linked to non-rapid eye movement sleep and electroencephalogram delta activity in humans. Conversely, hyperprolactinemia showed strong correlation with REM sleep in rodent studies. Prolactin may be implicated in the alterations in female sleep patterns observed during the reproductive cycle, it may play a role in the REM sleep enhancement following stress and in sleep-related immunological processes. In conclusion, prolactin appears to have a sleep-promoting role, particularly during the dark phase. However, it does not appear to play a central and coherent role in sleep regulation, as observed in some neuropeptides such as orexin. Conversely, its principal function may be to facilitate situational, yet adaptive, changes in sleep patterns in response to challenging physiological phases, such as those associated with stress, immunological challenges, or the reproductive cycle. Neuronal substrates for prolactin-mediated sleep effects remain unknown; however, recent rodent sleep studies may provide insights into the potential sites of these effects.

Overview of Hyperprolactinemia: General Approach and Reproductive Health Implications

Prolactin (PRL) is a polypeptide hormone produced by the lactotrope cells of the anterior pituitary gland. Among its myriads of biological functions, PRL is the main regulator of mammary gland growth and development, as well as of the production and secretion of milk. Hyperprolactinemia represents a frequent consultation cause in medical practice. Nevertheless, elevations in serum PRL are not always pathological. Drug induced hyperprolactinemia is the most common cause, mainly by antipsychotics, followed by other causes such as pituitary neuroendocrine tumors, physiologic conditions, and systemic diseases such as chronic kidney disease and hypothyroidism. When evaluating a patient with hyperprolactinemia it is of utmost importance to consider the diverse etiologies of this condition in order to avoid unnecessary diagnostic workup and treatment. Regarding reproductive health, hyperprolactinemia is a well-documented cause of infertility, as approximately 15-20% of women undergoing infertility evaluation have hyperprolactinemia, which causes secondary amenorrhea, and other menstrual irregularities. Similarly, in men it is a cause of hypogonadism.

Reference intervals for serum prolactin concentrations: analytical and clinical considerations

Prolactin is a 23 kDa protein synthesised and released by lactotrophs located in the anterior pituitary gland. The main function of prolactin is the development of the mammary glands and the production and maintenance of milk secretion during pregnancy and lactation. Prolactin is present in 3 forms in the circulation monomeric, dimeric and macroprolactin which is one of the causes of variability between assay manufacturers. Although most assays have been standardised using the WHO's 3rd international standard there is still considerable variability between commercially available assays and as such laboratories need to establish their own reference intervals. Clinicians use reference intervals to distinguish between healthy and diseased individuals. Direct methods to establish reference intervals are expensive and time consuming and are impractical for most routine clinical laboratories. Indirect methods using the laboratories own data are more commonly used but also have drawbacks. Determination of reference intervals for prolactin is particularly difficult due to various physiological causes for variation in prolactin levels including age, sex and menopause. The presence of macroprolactin, its detection and methods for reporting its presence adds to reference interval determination complexity and harmonisation of these methods may improve clinical care.

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

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

Prolactin's paradox: Friend, foe, or both in immune regulation?

Over 100 diseases have been recognized as autoimmune in nature, collectively affecting ∼20 % of the population in industrialized countries. These conditions are more prevalent among women of childbearing age, reflecting the potential association between alterations in the immune-neuroendocrine network, on the one hand, and autoimmune conditions, on the other. Prolactin (PRL), a polypeptide hormone that is primarily (but not only) secreted by the lactotrophic cells of the pituitary gland, is a critical element of the immune-neuroendocrine network. Although this hormone has several nonimmune functions, its role in regulating immune responses and affecting autoimmune inflammation is particularly enigmatic and controversial. Indeed, PRL interacts with various immune cells to bolster the body defenses, but also potentially to exacerbate autoimmune conditions. Understanding how and when PRL acts as a 'friend or foe' is crucial for unraveling its role as a potential therapeutic target in the management of autoimmune diseases (AIDs). This review therefore provides a critical overview of PRL's role in the immune system, and of the influence of this pleiotropic hormone in the development of autoimmunity.

Advancement in perioperative management of pituitary adenomas-Current concepts and best practices

Pituitary adenomas are very common representing 18.1% of all brain tumors and are the second most common brain pathology. Transsphenoidal surgery is the mainstay of treatment for all pituitary adenomas except for prolactinomas which are primarily treated medically with dopamine agonists. A thorough endocrine evaluation of pituitary adenoma preoperatively is crucial to identify hormonal compromise caused by the large sellar mass, identifying prolactin-producing tumors and comorbidities associated with Cushing and acromegaly to improve patient care and outcome. Transsphenoidal surgery is relatively safe in the hands of experienced surgeons, but still carries a substantial risk of causing hypopituitarism that required close follow-up in the immediate postoperative period to decrease mortality. A multidisciplinary team approach with endocrinologists, ophthalmologists, and neurosurgeons is the cornerstone in the perioperative management of pituitary adenomas.

Ectopic acromegaly with tumoral range hyperprolactinemia and apoplexy with a dramatic regression of pituitary hyperplasia

Acromegaly due to ectopic secretion of growth hormone-releasing hormone (GHRH) is a rare disorder. The signs and symptoms of ectopic acromegaly are indistinguishable from acromegaly due to a somatotroph adenoma. A 35-year-old female presented with secondary amenorrhea for 10 years, intermittent headache, and reduced vision in both eyes for 4 years, which worsened over 4 months before presentation. Additionally, she was diagnosed with uncontrolled diabetes mellitus. On examination, she had coarse facial features, a fleshy nose, and acral enlargement. She had diminished visual acuity (left>right) and bitemporal hemianopia on perimetry. Biochemical investigations revealed elevated IGF-1 [588 ng/ml, reference range (RR) 100-242], markedly elevated basal growth hormone (>80 ng/ml; RR, 0.12-9.88), and hyperprolactinemia in the tumoral range (832 ng/ml; RR, 5-25). MRI sella demonstrated a 22×30×34mm sellar-suprasellar mass with T2 hypointensity. Chest imaging revealed a 75×87×106mm left lung mass, which was found to be a well-differentiated neuroendocrine tumor (NET) on biopsy. Plasma GHRH levels were elevated [38,088 ng/l; RR, <250-300], and a diagnosis of ectopic acromegaly secondary to lung neuroendocrine tumor was considered. During workup, the patient developed in-hospital pituitary apoplexy, which improved with medical management. After a left pneumonectomy, her clinical features of acromegaly improved, her diabetes underwent remission, and there was a marked reduction in plasma GHRH and pituitary size. Histopathology was suggestive of a neuroendocrine tumor, with immunohistochemistry positive for GHRH and negative for prolactin. Her final diagnosis was ectopic acromegaly due to GHRH secreting a lung NET with pituitary somatotroph and lactotroph pituitary hyperplasia and apoplexy in the hyperplastic pituitary.

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

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

Usefulness of prolactin levels in predicting the etiology of hyperprolactinemia in a cohort of 770 patients

Objective

Determining the etiology of hyperprolactinemia is fundamental for selecting the most appropriate treatment strategy. The aim of this study was to evaluate the usefulness and accuracy of prolactin levels in predicting the etiology of nonphysiological hyperprolactinemia.

Subjects and methods

In this retrospective study, we reviewed medical records of patients with nonphysiological hyperprolactinemia seen at two neuroendocrine reference centers located in Recife, Brazil, from January 2000 to December 2019.

Results

The study included 770 patients aged 12-73 years (65% female). The three most frequent etiologies of hyperprolactinemia were prolactinomas (n = 263; 34.2%), drug-induced hyperprolactinemia (n = 160; 20.8%), and macroprolactinemia (n = 120; 15.6%). The highest mean prolactin levels were observed in cases of prolactinomas and idiopathic hyperprolactinemia. Most patients with hyperprolactinemia due to other etiologies had prolactin levels < 100 ng/mL, but these levels were also found in 16.5% of patients with microproplactinomas and in 20% of those with idiopathic hyperprolactinemia. Likewise, prolactin levels largely overlapped among patients with microprolactinomas, macroprolactinemia, and drug-induced hyperprolactinemia. Notably, prolactin levels > 250 ng/mL enabled a clear distinction between the etiologies of macroprolactinoma and nonfunctioning pituitary adenoma. Moreover, prolactin levels > 500 ng/mL were highly suggestive of macroprolactinomas, although they were also found in very few patients (<2%) with microprolactinomas or drug-induced hyperprolactinemia.

Conclusion

Despite considerable overlap in prolactin levels among the different etiologies of hyperprolactinemia, values > 250 ng/mL allowed a clear distinction between macroprolactinomas and nonfunctioning pituitary adenomas. Furthermore, prolactin levels > 500 ng/mL were almost exclusively found in patients with prolactinomas.

Determination of the frequency of hyperprolactinemia-related etiologies and the etiology-specific mean prolactin levels

BACKGROUND

Prolactin (PRL) is a peptide hormone secreted by the anterior pituitary that provides lactation during the postpartum period. The causes of hyperprolactinemia are pituitary tumors, medications, primary hypothyroidism, polycystic ovary syndrome (PCOS), renal failure, idiopathic, and other physiological causes such as pregnancy and lactation. In this study, we aimed to investigate the prevalence of hyperprolactinemia etiologies and the mean/median prolactin levels in different etiologies.

METHODS

The patients admitted to our outpatient clinic between January 2009-December 2019 were retrospectively screened from our hospital database with ICD-10 codes. Four hundred patients were included in the study; 69.5% of the patients were women. Their mean age was 43.67±13.42 years, the duration of illness was 7.8±5.6 years. The most frequent causes of hyperprolactinemia were found as follows: 52.5% (N.=210) prolactinoma, 7% (N.=28) gonadotropinoma, 6.5% (N.=26) drug-related, 6.5% (N.=25) PCOS, 5.8% (N.=23) idiopathic, 5% (N.=20) acromegaly, 4.8% (N.=19) nonfunctioning adenoma 2.3% (N.=9) craniopharyngioma. Patients with gonodotropinoma were significantly older, and the patients with PCOS were significantly younger than the patients with hyperprolactinemia due to the other etiologies. Patients with prolactinoma had significantly higher prolactin levels and longer duration of the illness when compared to other etiologies of hyperprolactinemia (168.00* ng/mL [14-23,500] [168]); 8* years (0-39) (5.00) years respectively, *median values, (min-max levels) and (interquartile range), respectively.

RESULTS

There was no significant difference between prolactin levels of other etiologic groups except prolactinoma. Surprisingly, we found PCOS patients with prolactin levels greater than 100 ng/mL and acromegaly or drug-induced hyperprolactinemia with prolactin levels greater than 200 ng/mL. In our study, unlike the literature, macroprolactinemia can be seen alone or together with other pathologies. Except for macroprolactinoma, it is not possible to diagnose according to prolactin level. Similar to the literature, prolactinoma was the most common cause of hyperprolactinemia. The causes of hyperprolactinemia, in order of decreasing frequency, were determined to be gonodotropinoma, drug-related, PCOS, idiopathic, and acromegaly. The range of prolactin detected in PCOS is given as new information. It was found that the pediatric group and the adult group had a similar etiology and PRL level.

CONCLUSIONS

A large spectrum of physiologic/pathologic conditions increases the prolactin levels, and prolactin levels may vary from person to person. So, the serum prolactin level alone does not guide a clinical diagnosis or make a differential diagnosis.

The Association between Vitamin D Status and the Impact of Metformin on Hypothalamic-Pituitary-Thyroid Axis Activity in Women with Subclinical Hypothyroidism

Metformin inhibits enhanced secretion of anterior pituitary hormones. Its impact on prolactin and gonadotropin concentrations is absent in individuals with hypovitaminosis D. The aim of this prospective cohort study was to investigate whether vitamin D status determines the effect of metformin on hypothalamic-pituitary-thyroid axis activity in levothyroxine-naïve women. The study included three groups of women of reproductive age with subclinical non-autoimmune hypothyroidism, which were matched for age, thyroid-stimulating hormone (TSH) concentration, and insulin sensitivity: untreated women with vitamin D deficiency/insufficiency (group A), women effectively supplemented with exogenous calciferol (group B), and untreated women with normal 25-hydroxyvitamin D concentrations (25OHD) (group C). Owing to concomitant type 2 diabetes or prediabetes, all subjects were treated with metformin. Concentrations of 25OHD, TSH, total and free thyroid hormones, glucose, insulin, glycated hemoglobin (HbA1c), prolactin, and peripheral markers of thyroid hormone action were assayed before metformin treatment and six months later. Based on hormone concentration, structure parameters of thyroid homeostasis were calculated. Except for 25OHD concentrations, there were no between-group differences in baseline values of the measured variables. Metformin reduced glucose, the homeostatic model assessment 1 of insulin resistance ratio (HOMA1-IR), and HbA1c in all study group, but these effects were less pronounced in group A than in the remaining groups. The reduction in TSH and Jostel's index was observed only in groups B and C, and its degree correlated with baseline TSH concentrations, baseline 25OHD concentrations, and the degree of improvement in HOMA1-IR. The drug did not affect circulating levels of 25OHD, free and total thyroid hormones, prolactin, other structure parameters of thyroid homeostasis, and markers of thyroid hormone action. The obtained results allow us to conclude that low vitamin D status in young women mitigates the impact of metformin on thyrotroph secretory function.

Clinical and radiographic characteristics of patients with non-functioning pituitary adenomas categorized according to their serum prolactin concentration: novel predictors of postoperative transient diabetes insipidus following surgery

PURPOSE

Non-functioning pituitary adenomas (NFPAs) are often associated with hyperprolactinemia, which is known as the "stalk effect". However, the relationships between hyperprolactinemia and the radiographic characteristics of the tumor that affects the pituitary stalk have not been well characterized. We aimed to identify the differences in the clinical and radiographic characteristics of patients with NFPA, with and without hyperprolactinemia.

METHODS

We enrolled 107 patients with NFPA and allocated them to hyperprolactinemia and non-hyperprolactinemia groups using two different cut-off values: (1) the upper limit of the normal reference range, adjusted for sex and menopausal status, and (2) the upper quartile across the cohort, and compared their clinical and radiographic characteristics. These analyses were conducted to clarify the relationship between the "stalk effect" and the postoperative change in antidiuretic hormone secretion.

RESULTS

The specific radiographic characteristics of the patients included the presence of a cystic or hemorrhagic tumor and the presence of pituitary stalk deviation, which were more frequent in the patients with hyperprolactinemia. Interestingly, the incidence of postoperative transient diabetes insipidus was statistically significantly higher in the hyperprolactinemia group (≥40 ng/mL) and in the group with radiologic evidence of stalk deviation, which were shown to be independent risk factors on multivariate analysis.

CONCLUSION

The presence of a "stalk effect" was associated with a higher risk of postoperative transient diabetes insipidus, reflecting perioperative pituitary stalk dysfunction following NFPA surgery, especially in patients with serum prolactin concentrations ≥40 ng/mL and radiologic evidence of stalk deviation.

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: A Mammalian Stress Hormone and Its Role in Cutaneous Pathophysiology

The hormone prolactin (PRL) is best recognised for its indispensable role in mammalian biology, specifically the regulation of lactation. Bearing in mind that the mammary gland is a modified sweat gland, it is perhaps unsurprising to discover that PRL also plays a significant role in cutaneous biology and is implicated in the pathogenesis of a range of skin diseases, often those reportedly triggered and/or exacerbated by psychological stress. Given that PRL has been implicated in over 300 biological processes, spanning reproduction and hair growth and thermo- to immunoregulation, a comprehensive understanding of the relationship between PRL and the skin remains frustratingly elusive. In an historical curiosity, the first hint that PRL could affect skin biology came from the observation of seborrhoea in patients with post-encephalitic Parkinsonism as a result of another global pandemic, encephalitis lethargica, at the beginning of the last century. As PRL is now being postulated as a potential immunomodulator for COVID-19 infection, it is perhaps timeous to re-examine this pluripotent hormone with cytokine-like properties in the cutaneous context, drawing together our understanding of the role of PRL in skin disease to illustrate how targeting PRL-mediated signalling may represent a novel strategy to treat a range of skin diseases and hair disorders.

Delusion of pregnancy: Case series

Delusion of pregnancy is a relatively uncommon manifestation in psychotic patients. Differentiating it from closely related clinical entities like pseudocyesis/pseudopregnancy can be a challenge in clinical setting. Diagnosis of a psychotic illness with delusional pregnancy as the presenting feature in the absence of other florid symptoms of psychosis is a different challenge altogether. Currently, there is no consensus on the pharmacotherapy and psychotherapy of delusional pregnancy. We present a case series on delusional pregnancy with the intent to answer some of these gaps in the literature.

A comprehensive review of the new FIGO classification of ovulatory disorders

BACKGROUND

The World Health Organization (WHO) system for the classification of disorders of ovulation was produced 50 years ago and, by international consensus, has been updated by the International Federation of Gynecology and Obstetrics (FIGO).

OBJECTIVE AND RATIONALE

This review outlines in detail each component of the FIGO HyPO-P (hypothalamic, pituitary, ovarian, PCOS) classification with a concise description of each cause, and thereby provides a systematic method for diagnosis and management.

SEARCH METHODS

We searched the published articles in the PubMed database in the English-language literature until October 2022, containing the keywords ovulatory disorders; ovulatory dysfunction; anovulation, and each subheading in the FIGO HyPO-P classification. We did not include abstracts or conference proceedings because the data are usually difficult to assess.

OUTCOMES

We present the most comprehensive review of all disorders of ovulation, published systematically according to the logical FIGO classification.

WIDER IMPLICATIONS

Improving the diagnosis of an individual's ovulatory dysfunction will significantly impact clinical practice by enabling healthcare practitioners to make a precise diagnosis and plan appropriate management.

Macroprolactin over time: Is there any point in rechecking it in people with a persistently elevated serum prolactin?

OBJECTIVE AND DESIGN

Macroprolactinemia may influence the interpretation of serum prolactin levels-a recognised phenomenon since 1981. The degree of macroprolactinaemia over time is less well described. We determined how macroprolactin status (based on polyethylene glycol (PEG) precipitation) varied by analysing serial measurements in hyperprolactinaemic individuals over a period of 9 years.

PATIENTS AND MEASUREMENTS

Results from 1810 individuals were included. All serum total prolactin results (measured using Roche Cobas 8000 analyser) were extracted from the laboratory information system for the period 1 January 2012 to 1 April 2021, along with relevant patient demographic/test data. Samples with a macroprolactin screening test performed (on samples with prolactin > 700 miu/L) were included in the main analysis.

RESULTS

During the study period, 2782 macroprolactin checks were performed (12.5% of all prolactin tests) in 1810 individuals (599 males/2183 females, median-age: 35, interquartile range: 25-47, range: 16-93 years). Multiple macroprolactin checks were carried out on 465 patients (1437 measurements) with 94 patients (141 measurements) screening positive (<60% recovery). Only 19 patients (18 female) had at least one result above and one below the 60% screening cut-off, with 10 of these patients having results close to the 60% cut-off; in 9 patients, results were clearly different between repeat samples. In seven cases, the adjusted monomeric prolactin showed a potentially clinically significant difference.

CONCLUSIONS

In this study, only 19/465 patients appeared to change macroprolactin status based on a 60% PEG recovery cut-off. The majority of these 19 patients were on antipsychotic/antidepressant medication(s) or had a prolactinoma; in only 7 did monomeric prolactin change significantly. This suggests that once macroprolactin status has been determined, clinical decision making is rarely affected by repeating it.

Diagnosis of hyperprolactinemia in women: A Position Statement from the Brazilian Federation of Gynecology and Obstetrics Associations (Febrasgo) and the Brazilian Society of Endocrinology and Metabolism (SBEM)

Hyperprolactinemia is a frequent cause of menstrual irregularity, galactorrhea, hypogonadism, and infertility. The most common etiologies of hyperprolactinemia can be classified as physiological, pharmacological, and pathological. Among pathological conditions, it is essential to distinguish prolactinomas from other tumors and pituitary lesions presenting with hyperprolactinemia due to pituitary stalk disconnection. Proper investigation considering clinical data, laboratory tests, and, if necessary, imaging evaluation, is important to identify the correctcause of hyperprolactinemia and manage the patient properly. This position statement by the Brazilian Federation of Gynecology and Obstetrics Associations (Febrasgo) and Brazilian Societyof Endocrinology and Metabolism (SBEM) addresses the recommendations for measurement of serum prolactin levels and the investigations of symptomatic and asymptomatic hyperprolactinemia and medication-induced hyperprolactinemia in women.

The Role of Artificial Intelligence in Endocrine Management: Assessing ChatGPT's Responses to Prolactinoma Queries

This research investigates the utility of Chat Generative Pre-trained Transformer (ChatGPT) in addressing patient inquiries related to hyperprolactinemia and prolactinoma. A set of 46 commonly asked questions from patients with prolactinoma were presented to ChatGPT and responses were evaluated for accuracy with a 6-point Likert scale (1: completely inaccurate to 6: completely accurate) and adequacy with a 5-point Likert scale (1: completely inadequate to 5: completely adequate). Two independent endocrinologists assessed the responses, based on international guidelines. Questions were categorized into groups including general information, diagnostic process, treatment process, follow-up, and pregnancy period. The median accuracy score was 6.0 (IQR, 5.4-6.0), and the adequacy score was 4.5 (IQR, 3.5-5.0). The lowest accuracy and adequacy score assigned by both evaluators was two. Significant agreement was observed between the evaluators, demonstrated by a weighted κ of 0.68 (p = 0.08) for accuracy and a κ of 0.66 (p = 0.04) for adequacy. The Kruskal-Wallis tests revealed statistically significant differences among the groups for accuracy (p = 0.005) and adequacy (p = 0.023). The pregnancy period group had the lowest accuracy score and both pregnancy period and follow-up groups had the lowest adequacy score. In conclusion, ChatGPT demonstrated commendable responses in addressing prolactinoma queries; however, certain limitations were observed, particularly in providing accurate information related to the pregnancy period, emphasizing the need for refining its capabilities in medical contexts.

Current Insights in Prolactin Signaling and Ovulatory Function

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

Prognostic factors for surgical treatment of prolactin-secreting pituitary adenomas

Introduction

Usually, prolactinomas are treated with dopamine agonists (DA). Surgery is considered an option when the patient cannot bear or does not respond positively to DA therapy.

Aim

This study aims to determine the early and late outcomes of surgery, with particular emphasis on developing prognostic factors for surgical treatment and analyzing risk factors affecting the recurrence of hyperprolactinemia and prolactinoma.

Material and methods

This retrospective study was conducted at the Feofaniya Clinical Hospital of the State Administration of Affairs (Kyiv, Ukraine), evaluating 109 patients' records from 2009 to 2019. The main patients' inclusion criteria were: serum prolactin (PRL) level of more than 100 ng/ml, presence of pituitary adenoma (PA) on MRI, histologically approved PA by microscopy. According to the size of the prolactin-secreting PA (PSPAs) the selected 109 patients were divided into two groups: micro- (≤10 mm, n = 75) and macroadenoma group (10-40 mm, n = 34).

Results

1 month after the operation, PRL levels decreased by 87% (p < 0.001), 12 months-by 93% (p < 0.001). After receiving surgery and DA therapy for 12 months 77.1% of patients achieved biochemical remission. Out of the total number of patients observed, 15.6% (n = 17) had a Knosp score greater than 3. Additionally, in the macroadenoma group, the percentage of patients with a Knosp score greater than 3 was 41,2%, which was significantly higher as compared to the microadenoma group (4%, p < 0.001). In patients with microadenomas a weak reverse correlation between patients' age (r = -0.258, p < 0.026) and positive with tumor size (r = 0.251, p < 0.030) was revealed. In the macroadenoma group significant association was found only between preoperative serum PRL level and tumor size (r = 0.412, p < 0.016). The preoperative PRL can be used as a diagnostic marker for lack of early biochemical remission in patients with PSPAs with diagnostic accuracy 66.9%.

Conclusions

This study found that primary transsphenoidal surgery is an effective treatment in reaching PRL level control in patients with both micro- and macroprolactinomas. The correct and thorough selection of candidates for surgery is crucial to achieve postoperative serum PRL normalization in the vast majority of patients.

Prolactin-secreting pituitary adenomas: male-specific differences in pathogenesis, clinical presentation and treatment

Prolactinomas (PRLomas) constitute approximately half of all pituitary adenomas and approximately one-fifth of them are diagnosed in males. The clinical presentation of PRLomas results from direct prolactin (PRL) action, duration and severity of hyperprolactinemia, and tumor mass effect. Male PRLomas, compared to females, tend to be larger and more invasive, are associated with higher PRL concentration at diagnosis, present higher proliferative potential, are more frequently resistant to standard pharmacotherapy, and thus may require multimodal approach, including surgical resection, radiotherapy, and alternative medical agents. Therefore, the management of PRLomas in men is challenging in many cases. Additionally, hyperprolactinemia is associated with a significant negative impact on men's health, including sexual function and fertility potential, bone health, cardiovascular and metabolic complications, leading to decreased quality of life. In this review, we highlight the differences in pathogenesis, clinical presentation and treatment of PRLomas concerning the male sex.

The relationship between plasma prolactin levels and clinical manifestations with neuromyelitis optica spectrum disorders

INTRODUCTION

Systemic prolactin levels have been found to increase in 19 patients diagnosed with neuromyelitis optica spectrum disorders (NMOSD). However, the relationship between plasma prolactin levels and clinical manifestations in NMOSD patients remains unclear.

METHODS

This cross-sectional study was conducted as part of a Registered Cohort Study of Inflammatory Demyelination Disease (NCT04386018). A total of 95 patients diagnosed with central nervous system demyelinating diseases and 43 healthy controls were recruited between May 2020 and February 2022 at the First Affiliated Hospital of Fujian Medical University. Plasma samples were collected from all participants and analyzed for prolactin levels using electrochemiluminescence immunoassay. The study aimed to investigate the correlation between plasma prolactin levels and clinical features in patients with central nervous system demyelinating diseases.

RESULTS

Plasma prolactin levels in NMOSD patients were significantly higher than those in multiple sclerosis/myelin oligodendrocyte glycoprotein antibody-associated diseases patients and controls (p<0.05, respectively), and were found to be correlated with disease activity, sensory abnormalities, thoracic spinal cord lesions, and MR lesion enhancement (p<0.05). A total of 16.28% of NMOSD patients exhibited macroprolactinemia. However, there was no correlation found between macroprolactin levels and disease activity (p>0.05).

CONCLUSION

Prolactin may play a role in the pro-inflammatory regulation mechanism of NMOSD.

The conceivable role of prolactin hormone in Parkinson disease: The same goal but with different ways

Parkinson disease (PD) is a progressive neurodegenerative disease (NDD) of the brain. It has been reported that prolactin (PRL) hormone plays a differential effect in PD, may be increasing, reduced or unaffected. PRL level is dysregulated in different neurodegenerative disorders including PD. Preclinical and clinical studies pointed out that PRL may has a neuroprotective against PD neuropathology . Though, the mechanistic role of PRL in PD is not fully elucidated. Therefore, the objective of the present review was to clarify the potential role and mechanistic pathway of PRL in PD neuropathology. The present review highlighted that PRL appears to have a neuroprotective effect against PD neuropathology by inhibiting the expression of pro-inflammatory signaling pathways, antioxidant effects and by inhibiting neuroinflammation. Thus, preclinical and clinical studies are warranted in this regard.

Protective effect of exogenous melatonin on testicular histopathology and histomorphometry of adult rats with domperidone-induced hyperprolactinemia

Hyperprolactinemia is a pathological condition resulting from increased prolactin that directly affects reproduction, as this condition inhibits the release of LH, FSH and gonadal steroidogenesis, bringing several negative clinical associations in reproduction. In contrast, melatonin (MEL) plays an important role in the regulation of steroidogenesis and modulates damages to the process of spermatogenesis. The objective was to analyze the protective effects of exogenous melatonin on the testis of hyperprolactinemic adult rats. Forty-eight male rats were used, divided into two treatment periods: 30 and 60 days, each treatment was subdivided into three groups: Control, Hyper (hyperprolactinemia), and Hyper+MEL (hyperprolactinemia and melatonin). Treatment with melatonin was 200 μg/100 g, subcutaneously. Induction of hyperprolactinemia was obtained with a dose of 4 mg/kg of domperidone, subcutaneously. The results of the histopathology demonstrated that the animals in the Hyper group presented degeneration of germ cells when compared to the control. In addition, the degenerations were presented in smaller quantities in the Hyper+MEL, in both treatment periods, evidencing the benefits of the melatonin in gonadal regeneration. The Hyper group of both treatment periods showed a decrease in tubular diameter, epithelium height, and tubular area, in addition to a decrease in Sertoli cells, when compared to the control and the Hyper+MEL group. In conclusion, the hyperprolactinemia can affect the germinal epithelium and testicular microstructure; the exogenous melatonin has a protective effect against hyperprolactinemia, reducing testicular damage.

Identifying a causal link between prolactin signaling pathways and COVID-19 vaccine-induced menstrual changes

COVID-19 vaccines have been instrumental tools in the fight against SARS-CoV-2 helping to reduce disease severity and mortality. At the same time, just like any other therapeutic, COVID-19 vaccines were associated with adverse events. Women have reported menstrual cycle irregularity after receiving COVID-19 vaccines, and this led to renewed fears concerning COVID-19 vaccines and their effects on fertility. Herein we devised an informatics workflow to explore the causal drivers of menstrual cycle irregularity in response to vaccination with mRNA COVID-19 vaccine BNT162b2. Our methods relied on gene expression analysis in response to vaccination, followed by network biology analysis to derive testable hypotheses regarding the causal links between BNT162b2 and menstrual cycle irregularity. Five high-confidence transcription factors were identified as causal drivers of BNT162b2-induced menstrual irregularity, namely: IRF1, STAT1, RelA (p65 NF-kB subunit), STAT2 and IRF3. Furthermore, some biomarkers of menstrual irregularity, including TNF, IL6R, IL6ST, LIF, BIRC3, FGF2, ARHGDIB, RPS3, RHOU, MIF, were identified as topological genes and predicted as causal drivers of menstrual irregularity. Our network-based mechanism reconstruction results indicated that BNT162b2 exerted biological effects similar to those resulting from prolactin signaling. However, these effects were short-lived and didn't raise concerns about long-term infertility issues. This approach can be applied to interrogate the functional links between drugs/vaccines and other side effects.

Macroprolactinemia: a mini-review and update on clinical practice

Hyperprolactinemia is common among infertile patients, with up to 15%-20% of women with oligomenorrhea having hyperprolactinemia. Suppression of the hypothalamic-pituitary-gonadal axis via inhibition of pulsatile gonadotropin releasing hormone because of hyperprolactinemia is a common endocrine etiology of infertility. There are 3 forms of human prolactin (PRL): monomeric PRL, dimeric PRL, and macro-PRL. Also known as big-big PRL, macro-PRL has a molecular weight >150 kDa and normally comprises 5%-10% of circulating PRL. When the predominant form of circulating PRL is macro-PRL, macroprolactinemia is diagnosed. Among patients with hyperprolactinemia, 10%-46% have macroprolactinemia. Patients with macroprolactinemia are at risk of unnecessary pituitary imaging and treatment with dopamine agonists if not correctly diagnosed. Given the high prevalence of macroprolactinemia among patients with elevated PRL levels and the different management of patients with macroprolactinemia vs true monomeric hyperprolactinemia, all patients with persistently elevated PRL levels should be screened for macro-PRL.

The Hook Effect: A Case Study of a Giant Invasive Prolactinoma With Falsely Low Serum Prolactin

Prolactinomas are benign pituitary tumors also known as prolactin-secreting adenomas (PSA). These tumors cause excessive secretion of prolactin (hyperprolactinemia), a hormone responsible for lactation. Diagnosing hyperprolactinemia relies on measuring prolactin levels in the blood, and elevated serum levels of prolactin are typically indicative of prolactinoma. The hook effect occurs in immunological tests such as the prolactin level test. When the amount of prolactin present in the sample is too high and exceeds the binding capacity of the antibodies being used, the test result may indicate falsely low levels of prolactin, which is the hook effect. The present study describes the case of a male patient who presented with neck pain and difficulty swallowing. MRI revealed a giant (>40mm) extradural tumor affecting the clivus, anterior fossa, pterygopalatine, and bilateral infratemporal fossae as well as the petrous apex and bilateral cavernous sinuses. Endocrinological investigation yielded no specific abnormalities. An occipitocervical fixation (arthrodesis) was proposed with simultaneous extended endoscopic endonasal resection. Surgery succeeded in resecting a portion of the clival tumor and the anterior fossa. Measurement of prolactin levels several weeks post-surgery found them to be extremely high, confirming the hook effect.

The effects of prolactin on the immune system, its relationship with the severity of COVID-19, and its potential immunomodulatory therapeutic effect

Prolactin (PRL) is an endocrine hormone secreted by the anterior pituitary gland that has a variety of physiological effects, including milk production, immune system regulation, and anti-inflammatory effects. Elevated levels of PRL have been found in several viral infections, including 2019 coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), a viral pathogen that has recently spread worldwide. PRL production is increased in SARS-CoV2 infection. While PRL can trigger the production of proinflammatory cytokines, it also has several anti-inflammatory effects that can reduce hyperinflammation. The exact mechanism of PRL's contribution to the severity of COVID-19 is unknown. The purpose of this review is to discuss the interaction between PRL and SARS-CoV2 infection and its possible association with the severity of COVID-19.

Current and Perspective Approaches to the Treatment of Prolactinomas

Background

Along with the presence of the 2011 Endocrine Society Clinical Practice Guidelines and numerous large-scale studies on the treatment of hyperprolactinemia of different origin, there are some unresolved questions, ambiguous and sometimes contradictory points of view regarding the management of patients with prolactinomas. This overview is devoted to the analysis of the results of modern clinical studies and the approaches towards the management of hyperprolactinemia caused by prolactinoma.

Materials and methods

A systematic research of the literature for the appropriate keywords published mainly for the last 10 years was done; also, a reference list of each selected article was analysed. We included to our review the articles reporting controversial issues or new data on the treatment of hyperprolactinemia.

Results

The review describes various problems arising during the treatment of prolactinoma. The presence of primary and secondary dopamine agonist resistance in each case requires an individual approach, and sometimes may include the use of the antineoplastic agent t emozolomide. The side effects of dopamine agonists are discussed, with quite rare ones, including valvulopathy, pathological psychological conditions and cerebrospinal rhinorrhea. The controversial issue of the duration and doses of the drug used to achieve a lasting effect in the treatment of prolactinomas is considered. There are some points connected with the frequency of relapses. Thus, recurrence is correlated to the duration of treatment with dopamine agonists, prolactin levels at diagnosis, and the initial tumor size. Metformin, somatostatin analogues, selective estrogen receptor modulators, tyrosine kinase inhibitors, inhibitors of the mammalian target of rapamycin, epidermal growth factor receptor antagonists are investigated nowadays as potential alternative methods of drug treatment of prolactinomas.

Conclusion

Drug therapy with dopamine agonists makes it possible to achieve the desired results in the vast majority of patients. However, despite the proven safety of this group of medicines, the risk of side effects should still be taken into account. The therapy regimen should be determined by the clinical course of prolactinoma and the patient's response to treatment. Other options of treatment should be considered in patients intolerant to medical therapy, with contraindication or resistance to dopamine agonists, in the case of a malignant tumor. The presence of refractory to any of the applied methods of treatment and aggressive prolactinomas leads to the search for new drugs.

Sexual Function and Depressive Symptoms in Young Women with Euthyroid Hashimoto's Thyroiditis Receiving Vitamin D, Selenomethionine and Myo-Inositol: A Pilot Study

Thyroid autoimmunity is associated with an increased risk of sexual dysfunction. The aim of this study was to compare sexual functioning and depressive symptoms in women with Hashimoto's thyroiditis receiving different treatments. The study included euthyroid women with autoimmune thyroiditis, untreated or receiving vitamin D, selenomethionine, or myo-inositol. Apart from measuring antibody titers and hormone levels, all participants completed questionnaires evaluating female sexual function (FSFI) and depressive symptoms (BDI-II). In untreated women, the overall FSFI scores and domain scores for desire, arousal, lubrication, and sexual satisfaction were lower than in women receiving vitamin D, selenomethionine, and myo-inositol. In the vitamin D-treated women, the total FSFI scores and scores for desire and arousal were higher than in women receiving the remaining micronutrients. The BDI-II score was lowest in the vitamin D-treated women and highest in the untreated patients with thyroiditis. Vitamin D-treated women were also characterized by lower antibody titers and higher testosterone levels than the women receiving the remaining micronutrients. There were no differences in sexual functioning and depressive symptoms between the selenomethionine- and myo-inositol-treated women. The study results suggest that although all antibody-lowering treatments are associated with better sexual functioning and well-being in young women with euthyroid autoimmune thyroiditis, the greatest benefits are observed in patients receiving vitamin D.

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.

A giant invasive macroprolactinoma with recurrent nasal bleeding as the first clinical presentation: case report and review of literature

BACKGROUND

Giant prolactinoma (> 4 cm in dimension) is a rare disorder. Invasive macroprolactinoma has the potential to cause base of skull erosion and extend into the nasal cavity or even the sphenoid sinus. Nasal bleeding caused by intranasal tumor extension is a rare complication associated with invasive giant prolactinoma. We report a case of giant invasive macroprolactinoma with repeated nasal bleeding as the initial symptom.

CASE PRESENTATION

A 24-year-old man with an invasive giant prolactinoma in the nasal cavity and sellar region who presented with nasal bleeding as the initial symptom, misdiagnosed as olfactory neuroblastoma. However, markedly elevated serum prolactin levels (4700 ng/mL), and a 7.8-cm invasive sellar mass confirmed the diagnosis of invasive giant prolactinoma. He was treated with oral bromocriptine. Serum prolactin was reduced to near normal after 6 months of treatment. Follow-up magnetic resonance imaging showed that the sellar lesion had disappeared completely and the skull base lesions were reduced.

CONCLUSION

This case is notable in demonstrating the aggressive nature of untreated invasive giant prolactinomas which can cause a diagnostic difficulty with potential serious consequences. Early detection of hormonal levels can avoid unnecessary nasal biopsy. Early identification of pituitary adenoma with nasal bleeding as the first symptom is particularly important.

Prolactin and oxytocin: potential targets for migraine treatment

Migraine is a severe neurovascular disorder of which the pathophysiology is not yet fully understood. Besides the role of inflammatory mediators that interact with the trigeminovascular system, cyclic fluctuations in sex steroid hormones are involved in the sex dimorphism of migraine attacks. In addition, the pituitary-derived hormone prolactin and the hypothalamic neuropeptide oxytocin have been reported to play a modulating role in migraine and contribute to its sex-dependent differences. The current narrative review explores the relationship between these two hormones and the pathophysiology of migraine. We describe the physiological role of prolactin and oxytocin, its relationship to migraine and pain, and potential therapies targeting these hormones or their receptors.In summary, oxytocin and prolactin are involved in nociception in opposite ways. Both operate at peripheral and central levels, however, prolactin has a pronociceptive effect, while oxytocin appears to have an antinociceptive effect. Therefore, migraine treatment targeting prolactin should aim to block its effects using prolactin receptor antagonists or monoclonal antibodies specifically acting at migraine-pain related structures. This action should be local in order to avoid a decrease in prolactin levels throughout the body and associated adverse effects. In contrast, treatment targeting oxytocin should enhance its signalling and antinociceptive effects, for example using intranasal administration of oxytocin, or possibly other oxytocin receptor agonists. Interestingly, the prolactin receptor and oxytocin receptor are co-localized with estrogen receptors as well as calcitonin gene-related peptide and its receptor, providing a positive perspective on the possibilities for an adequate pharmacological treatment of these nociceptive pathways. Nevertheless, many questions remain to be answered. More particularly, there is insufficient data on the role of sex hormones in men and the correct dosing according to sex differences, hormonal changes and comorbidities. The above remains a major challenge for future development.

Melatonin’s actions are not limited to sleep

Melatonin is widely available as a supplement, usually for sleep disorders. The consumption of melatonin supplements has increased considerably in recent years. An overlooked aspect of melatonin’s administration is the resulting increase in prolactin secretion, via its action on hypothalamic dopaminergic neurons. We believe that since the effect of melatonin on prolactin is tangible, the laboratory finding of hyperprolactinemia could be encountered more often, given the increase in melatonin’s use. This is an issue that merits further study.

Clinical Presentations of Drug-Induced Hyperprolactinaemia: A Literature Review

Screening for drug-induced hyperprolactinaemia, a condition characterised by higher-than-normal levels of serum prolactin induced by drug treatments, requires a comprehensive understanding of the clinical presentations and long-term complications of the condition. Using two databases, Embase and MEDLINE, we summarised the available evidence on the clinical presentations and long-term complications of drug-induced hyperprolactinaemia. Clinical and observational studies reporting on drug treatments known or suspected to induce hyperprolactinaemia were included. Database searches were limited to the English language; no date or geographic restrictions were applied. Fifty studies were identified for inclusion, comprising a variety of study designs and patient populations. Most data were reported in patients treated with antipsychotics, but symptoms were also described among patients receiving other drugs, such as prokinetic drugs and antidepressants. Notably, the diagnosis of drug-induced hyperprolactinaemia varied across studies since a standard definition of elevated prolactin levels was not consistently applied. Frequent clinical presentations of hyperprolactinaemia were menstrual cycle bleeding, breast or lactation disorders, and sexual dysfunctions, described in 80% (40/50), 74% (37/50), and 42% (21/50) of the included studies, respectively. In the few studies reporting such symptoms, the prevalence of vaginal dryness impacted up to 53% of females, and infertility in both sexes ranged from 15 to 31%. Clinicians should be aware of these symptoms related to drug-induced hyperprolactinaemia when treating patients with drugs that can alter prolactin levels. Future research should explore the long-term complications of drug-induced hyperprolactinaemia and apply accepted thresholds of elevated prolactin levels (i.e., 20 ng/mL for males and 25 ng/mL for females) to diagnose hyperprolactinaemia as a drug-induced adverse event.Trial Registration PROSPERO International Prospective Register Of Systematic Reviews (CRD42021245259).

1Progress, applications, challenges and prospects of protein purification technology

Protein is one of the most important biological macromolecules in life, which plays a vital role in cell growth, development, movement, heredity, reproduction and other life activities. High quality isolation and purification is an essential step in the study of the structure and function of target proteins. Therefore, the development of protein purification technologies has great theoretical and practical significance in exploring the laws of life activities and guiding production practice. Up to now, there is no forthcoming method to extract any proteins from a complex system, and the field of protein purification still faces significant opportunities and challenges. Conventional protein purification generally includes three steps: pretreatment, rough fractionation, and fine fractionation. Each of the steps will significantly affect the purity, yield and the activity of target proteins. The present review focuses on the principle and process of protein purification, recent advances, and the applications of these technologies in the life and health industry as well as their far-reaching impact, so as to promote the research of protein structure and function, drug development and precision medicine, and bring new insights to researchers in related fields.

Diagnostic value of magnetic resonance imaging ectopic posterior pituitary hyperintense signal in pituitary macroadenoma

Objective

When the lesions in the sellar region are large, they can involve both the inside and outside the sella, which brings challenges to the differential diagnosis of pituitary macroadenoma and lesions other than macroadenoma. Therefore, this study explored the diagnostic value of an ectopic posterior pituitary hyperintense signal (EPPHS) in pituitary macroadenoma and its possible causes.

Methods

The clinical and imaging data of 131 patients with sellar tumors or tumor-like lesions involving both intrasellar and extrasellar regions in the Affiliated Hospital of Guizhou Medical University from February 2011 to December 2021 were analyzed retrospectively. The diagnostic value of EPPHS in pituitary macroadenoma was analyzed. The differences in clinical and imaging indexes between the EPPHS-positive group and the EPPHS-negative group were compared.

Results

These 131 cases of sellar tumors or tumor-like lesions involving both intrasellar and extrasellar regions included 91 cases of pituitary macroadenoma and 40 cases of lesions other than macroadenoma. The receiver operator characteristic (ROC) curve analysis suggested that EPPHS had a diagnostic value in diagnosing pituitary macroadenoma [area under the curve (AUC) = 0.857, P = 0.0001]. Compared with the EPPHS negative group, the median prolactin level in the EPPHS positive group was significantly higher (P &lt; 0.05). Through ROC curve analysis, prolactin value was found to be of diagnostic value for EPPHS (AUC = 0.612, P = 0.0312).

Conclusion

In sellar tumors or tumor-like lesions involving both intrasellar and extrasellar regions, the appearance of EPPHS is helpful in the diagnosis of pituitary macroadenoma. The formation of EPPHS may be related to injuries to the pituitary stalk.

Venlafaxine-related galactorrhea in an adolescent female: A case report

Hyperprolactinemia with galactorrhea is a well-documented adverse effect of some psychotropic medications. While advanced practice psychiatric nurses are likely familiar with hyperprolactinemia with galactorrhea as an adverse effect of antipsychotics, they may be less familiar with hyperprolactinemia with galactorrhea associated with antidepressants, an adverse effect that is far less common. Advanced practice psychiatric nurses must be able to identify hyperprolactinemia and galactorrhea in patients and must be able to evaluate and manage antidepressant-related hyperprolactinemia with galactorrhea. Thus, this case report describes hyperprolactinemia with galactorrhea in a teenage female prescribed venlafaxine for the treatment of major depressive disorder and posttraumatic stress disorder. To our knowledge, this is the first case report that describes galactorrhea related to a reuptake inhibitor (SNRI) in an adolescent.

Epidemiological and clinical profiles of Saudi patients with hyperprolactinemia in a single tertiary care center

BACKGROUND

Prolactin is a hormone of the pituitary gland whose main function is the production of milk. Hyperprolactinemia is defined as an increase in prolactin levels above 25 μg/L in women and 20 μg/L in men. Causes of hyperprolactinemia include pituitary tumors, especially prolactinomas. Hyperprolactinemia can manifest clinically with a variety of symptoms, including galactorrhea and menstrual irregularities in women and erectile dysfunction in men. There are limited data on the epidemiology of hyperprolactinemia in the Middle East region.

OBJECTIVES

Description of the epidemiology and clinical features of hyperprolactinemia in a cohort from Saudi Arabia.

DESIGN

Medical record review SETTING: Tertiary medical center in Riyadh PATIENTS AND METHODS: The study included adult patients with hyperprolactinemia in King Abdulaziz Medical City in Riyadh. The patients were treated in endocrinology clinics from 2015 to 2019. Patients of both sexes older than 14 years were enrolled in the study. Patients with insufficient follow-up were excluded. Data were collected on demographic characteristics, symptoms, prolactin level, cause of high prolactin level, and treatment.

MAIN OUTCOME MEASURES

The frequency of different etiologies and symptoms in patients with hyperprolactinemia.

SAMPLE SIZE

295 patients RESULTS: The majority of patients with hyperprolactinemia were female 256 (86.8%). Hyperprolactinemia was diagnosed more frequently in patients in the age groups 21-30 years (42.6%) and 31-40 years (24.1%). The majority of the study population was obese or overweight: 136 (46.3%) and 74 (25.2%), respectively. Most of the cases were symptomatic (192, 65.1%). In women, the most common symptom was oligomenorrhea (35%). In men, infertility and erectile dysfunction were the most common clinical symptoms (50% and 44.7%, respectively). Idiopathic causes were the most common etiology (108, 36.6%), followed by pituitary adenomas (81, 27.5%). The majority of patients were treated (184,62.4%), with cabergoline being the most commonly used medication (173, 94.0%).

CONCLUSION

The demographic and clinical presentations and causes of hyperprolactinemia in male and female Saudi patients were similar to that in studies in other populations.

LIMITATIONS

Single-center retrospective chart review study.

CONFLICT OF INTEREST

None.

Prolactin immunoassay: does the high-dose hook effect still exist?

PURPOSE

Measurement of prolactin in clinical laboratories is an important component in the management of patients with pituitary adenoma. Prolactin measurement is known to be sensitive to the high-dose hook effect, in the presence of extremely high prolactin concentrations. This interference is referred to in most recent articles discussing prolactin assays and the management of prolactin-secreting pituitary adenomas. The objective of our study was to evaluate if the high-dose hook effect remains relevant in current practice, when using currently available assays.

METHODS

Serum from a patient with a giant macroprolactinoma was assayed using all of the available prolactin assays in France in 2020, using native serum and after dilution. Technical inserts from assays were reviewed to assess the information on analytical principles, numbers of steps, and any reference to high dose hook effect.

RESULTS

Fourteen assay kits were studied by 16 laboratories; all were two-site immunometric assays, mostly using one step (11/14). Results obtained after dilution varied from 17,900 µg/L to 86,900 µg/L depending on the assay used. One tested assay was sensitive to the high-dose hook effect leading to a falsely lower prolactin concentration when measuring native serum (150 µg/L compared to 17,900 µg/L after dilution).

CONCLUSION

The high-dose hook effect still exists in a very small minority of prolactin assays. The evolution of assay methods may lead to new assays that remain sensitive to this effect in the future. We therefore advise that the hook effect should still be mentioned in prolactin assay recommendations.

The crucial role of prolactin-lactogenic hormone in Covid-19

Prolactin (PRL) is a peptide hormone secreted from anterior pituitary involved in milk production in the females and regulation of sex drive in both sexes. PRL has pro-inflammatory and anti-inflammatory functions. High PRL serum level or hyperprolactinemia is associated with different viral infections. In coronavirus disease 2019 (Covid-19), which caused by positive-sense single-strand RNA virus known as severe acute respiratory distress syndrome coronavirus type 2 (SARS-CoV-2), PRL serum level is increased. PRL in Covid-19 may exacerbate the underlying inflammatory status by induction release of pro-inflammatory cytokines. However, PRL through its anti-inflammatory effects may reduce the hyperinflammatory status in Covid-19. The underlying mechanism of increasing PRL in Covid-19 is poorly understood. Therefore, in this review we try to find the potential anti-inflammatory or pro-inflammatory role of PRL in Covid-19. As well, this review was aimed to discuss the underlying causes and mechanisms for Covid-19-induced hyperprolactinemia.

Italian Association of Clinical Endocrinologists (AME) and International Chapter of Clinical Endocrinology (ICCE). Position statement for clinical practice: prolactin-secreting tumors

Prolactinomas are the most frequent pituitary adenomas. Prolactinoma may occur in different clinical settings and always require an individually tailored approach. This is the reason why a panel of Italian neuroendocrine experts was charged with the task to provide indications for the diagnostic and therapeutic approaches that can be easily applied in different contexts. The document provides 15 recommendations for diagnosis and 54 recommendations for treatment, issued according to the GRADE system. The level of agreement among panel members was formally evaluated by RAND-UCLA methodology. In the last century, prolactinomas represented the paradigm of pituitary tumors for which the development of highly effective drugs obtained the best results, allowing to avoid neurosurgery in most cases. The impressive improvement of neurosurgical endoscopic techniques allows a far better definition of the tumoral tissue during surgery and the remission of endocrine symptoms in many patients with pituitary tumors. Consequently, this refinement of neurosurgery is changing the therapeutic strategy in prolactinomas, allowing the definitive cure of some patients with permanent discontinuation of medical therapy.

Serum prolactin level to tumor size ratio as a potential parameter for preoperative differentiation of prolactinomas from hyperprolactinemia-causing non-functional pituitary adenomas

OBJECTIVE

Preoperative diagnosis of prolactinomas is critical because dopamine agonists have been regarded as a primary treatment. However, serum prolactin level alone is suboptimal for differentiating prolactinomas from hyperprolactinemia-causing non-functioning pituitary adenomas (NFPAs). By using the tumor size, the authors tried to investigate an effective parameter for the discrimination.

METHODS

We performed a retrospective review of patients who underwent trans-sphenoidal surgery for pituitary lesions in a single institute between January 2015 and May 2021. Using the receiver operating curve (ROC) analyses, we compared performances of serum prolactin levels (PRL), a ratio of serum PRL levels to maximal tumor diameter (MD) (PRL/MD; PDR1), and MD squared (PRL/[MD]²; PDR2) in preoperative diagnosis of prolactinomas.

RESULTS

223 patients with NFPAs (n=175) and prolactinomas (n=48) were included in the analysis. A moderate correlation was found between serum prolactin levels and MDs in prolactinomas (pearson's r_prl=0.43, p=0.002), whereas a weak correlation was observed in NFPAs (pearson's r_nfpa=0.17, p=0.028). Among diagnostic parameters, PDR2 exhibited the optimal diagnostic performance with the cutoff value of 0.83 [㎍/L]/mm² (area under the curve [AUC] = 0.945), compared to the PDR1 (8.93 [㎍/L]/mm with AUC 0.938) and PRL (99.4 ㎍/L with AUC 0.910). In the external validation study, PDR2 maintained superior performance over PDR1 and PRL (Accuracy of 94.8%, 91.8%, and 75.8%, respectively).

CONCLUSIONS

PDR2 was a more effective indicator than prolactin alone in the preoperative differential diagnosis of prolactinomas and NFPAs, which may help select patients who need medical treatment first.

Outcomes of transsphenoidal surgery in dopamine agonist-resistant prolactinomas: a retrospective study

PURPOSE

Dopamine agonists (DA) comprise first-line treatment for prolactinomas. However, some patients show no response to DA and are considered resistant. In this study, we retrospectively analyzed the outcomes of DA-resistant prolactinoma patients after transsphenoidal surgery (TSS).

METHODS

A total of 94 consecutive patients with DA-resistant prolactinomas who underwent TSS were retrospectively enrolled in the present study. Early postoperative remission rate, prolactin (PRL) levels, and recurrence rate were analyzed.

RESULTS

Of 94 DA-resistant patients, 47 (50%) achieved early remission 1 week post-surgery, including 41.18% of macroprolactinoma patients and 73.08% of microprolactinoma patients. PRL levels on the first postoperative day were significantly lower than preoperative PRL levels (p < 0.001). Total resection rate in macro- and microprolactinomas were, respectively, 75 and 96.15%. A recurrence of hyperprolactinemia and tumor was, respectively, found in 31.91 and 19.15% of patients with a follow-up of 39.53 ± 2.172 months (range 3-86). A higher hyperprolactinemia recurrence was observed in patients with invasive prolactinomas (p = 0.021) or preoperative PRL levels ≥ 200 ng/ml (p = 0.029). Univariate logistic regression indicated that larger maximum tumor diameter (p = 0.045), invasive prolactinomas (p = 0.002), and absence of early postoperative remission (p = 0.004) were significant predictors of tumor recurrence. However, using multivariate stepwise logistic regression, only invasiveness and early postoperative remission remained significant.

CONCLUSION

Tumor invasiveness and preoperative PRL levels were significant predictors of hyperprolactinemia recurrence after TSS. For tumor recurrence, invasiveness and early postoperative remission were independent predictors.

The Relationship Between Bone and Reproductive Hormones Beyond Estrogens and Androgens

Reproductive hormones play a crucial role in the growth and maintenance of the mammalian skeleton. Indeed, the biological significance for this hormonal regulation of skeletal homeostasis is best illustrated by common clinical reproductive disorders, such as primary ovarian insufficiency, hypothalamic amenorrhea, congenital hypogonadotropic hypogonadism, and early menopause, which contribute to the clinical burden of low bone mineral density and increased risk for fragility fracture. Emerging evidence relating to traditional reproductive hormones and the recent discovery of newer reproductive neuropeptides and hormones has deepened our understanding of the interaction between bone and the reproductive system. In this review, we provide a contemporary summary of the literature examining the relationship between bone biology and reproductive signals that extend beyond estrogens and androgens, and include kisspeptin, gonadotropin-releasing hormone, follicle-stimulating hormone, luteinizing hormone, prolactin, progesterone, inhibin, activin, and relaxin. A comprehensive and up-to-date review of the recent basic and clinical research advances is essential given the prevalence of clinical reproductive disorders, the emerging roles of upstream reproductive hormones in bone physiology, as well as the urgent need to develop novel safe and effective therapies for bone fragility in a rapidly aging population.