Prolactin as a neuroendocrine clue in sexual function of women across the reproductive life cycle: an expert point of view.

Prolactin is a proteic hormone best known for its role in enabling the production of milk by female mammals. Secreted by the pituitary gland in response to the stimuli of eating, estrogen treatment, mating, ovulation and nursing, prolactin is involved in over 300 separate processes in a range of vertebrates, including humans. The hormone is released in a pulsatile manner and plays an essential role in metabolism, as well as in the regulation of the immune system and pancreatic development. Nevertheless, prolactin exerts other relevant roles, as it acts at the central nervous system level to modulate behavior, arousal and sexuality. In this experts' opinion, we aim to give insights into the main activities of prolactin to advance the ability of medical doctors and specialists in obstetrics and gynecology to provide more emphasis in their clinical practices to the link between prolactin and sexuality.

[Research progress of kisspeptin in female reproductive endocrine and assisted reproductive techniques].

In recent years, it has been found that kisspeptin plays some key roles in the physiological processes of the brain, such as gender differentiation, positive and negative feedback of sex hormones, onset of puberty, and transduction of energy signals in the body, which suggests that kisspeptin may be a key molecule for the maturation and regulation of female reproductive function. In addition to the systemic roles of the kisspeptin, its local roles in reproductive organs are constantly being discovered. With the discovery that kisspeptin is involved in the pathological process of reproductive endocrine diseases such as isolated hypogonadotropic hypogonadism (IHH), polycystic ovary syndrome (PCOS), premature ovarian failure (POF) and pathological hyperprolactinemia, exogenous application of kisspeptin to solve reproductive problems has become a new hot topic. The review focuses on the research progress of kisspeptin in the female reproductive system, especially on its application in assisted reproduction.

Hyperprolactinemic African elephant (Loxodonta africana) females exhibit elevated dopamine, oxytocin and serotonin concentrations compared to normal cycling and noncycling, low prolactin elephants†.

Many zoo elephants do not cycle normally, and for African elephants, it is often associated with hyperprolactinemia. Dopamine agonists successfully treat hyperprolactinemia-induced ovarian dysfunction in women, but not elephants. The objective of this study was to determine how longitudinal dopamine, serotonin, and oxytocin patterns in African elephants are related to ovarian cycle function. We hypothesized that dopamine concentrations are decreased, while oxytocin and serotonin are increased in non-cycling, hyperprolactinemic African elephants. Weekly urine and serum samples were collected for eight consecutive months from 28 female African elephants. Females were categorized as follows: (1) non-cycling with average prolactin concentrations of 15 ng/ml or greater (HIGH; n = 7); (2) non-cycling with average prolactin concentrations below 15 ng/ml (LOW; n = 13); and (3) cycling with normal progestagen and prolactin patterns (CYCLING; n = 8). Both oxytocin and serotonin were elevated in hyperprolactinemic elephants. Thus, we propose that stimulatory factors may play a role in the observed hyperprolactinemia in this species. Interestingly, rather than being reduced as hypothesized, urinary dopamine was elevated in hyperprolactinemic elephants compared to CYCLING and LOW prolactin groups. Despite its apparent lack of regulatory control over prolactin, this new evidence suggests that dopamine synthesis and secretion are not impaired in these elephants, and perhaps are augmented.

Hypothalamic-pituitary-gonadal axis dysfunction: An innate pathophysiology of schizophrenia?

The female hormone 17ß-estradiol is postulated to be protective against schizophrenia onset and severity. Hypoestrogenism is a common phenomenon in women with schizophrenia that has serious effects that adds to the burden of an already very onerous disease. The cause of hypoestrogenism is largely attributed to antipsychotic-induced hyperprolactinemia. Evidence suggest however that a significant portion of female schizophrenia patients develop hypoestrogenism either before antipsychotic treatment or without regard to the level of prolactin, suggesting that for a sizeable segment of female patients, gonadal abnormality may be an innate and early aspect of the disease. This review aims to summarise the available literature that examines gonadal dysfunction in schizophrenia through this prism as well as to outline some recent developments in treatment strategies that may provide feasible ways to successfully tackle hypoestrogenism in schizophrenia.

No impact of treated hyperprolactinemia on cumulative live birth rate and perinatal outcomes in in vitro fertilization-embryo transfer.

AIM: To investigate whether treated hyperprolactinemia has an impact on pregnancy outcomes in in vitro fertilization/intracytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET). METHODS: A retrospective cohort study was conducted on 535 women who underwent IVF/ICSI-ET between January 2012 and December 2016, of which 123 had treated hyperprolactinemia (case group), 369 were matched controls. Besides, 43 remained hyperprolactinemic after treatment consisted of abnormal group. Cumulative live birth rate (CLBR) after one oocyte retrieval cycle was taken as the primary outcome. A time-to-event analysis using Fine and Gray's test was used to compare CLBR between case and control groups. RESULTS: The median prolactin level was 80.00 ng/mL before dopamine agonist treatment in case group, and it reduced to 14.80 ng/mL after the treatment, similar to the level of control group (15.17 ng/mL, P = 0.316). No significant differences in baseline characteristics were found between case and control groups. The CLBR after one oocyte retrieval cycle were 69.1% (85/123) and 66.4% (245/369) in the case group and control group, respectively (P = 0.580). No significant differences were found between case and control groups in perinatal outcomes. Pregnancy and perinatal outcomes of abnormal group were similar to those of case and control groups. CONCLUSION: Impact of treated hyperprolactinemia on CLBR and perinatal outcomes in IVF-ET was not evident.

Antipsychotic-induced hyperprolactinaemia: case studies and review.

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

The hormone prolactin is a novel, endogenous trophic factor able to regulate reactive glia and to limit retinal degeneration.

Retinal degeneration is characterized by the progressive destruction of retinal cells, causing the deterioration and eventual loss of vision. We explored whether the hormone prolactin provides trophic support to retinal cells, thus protecting the retina from degenerative pressure. Inducing hyperprolactinemia limited photoreceptor apoptosis, gliosis, and changes in neurotrophin expression, and it preserved the photoresponse in the phototoxicity model of retinal degeneration, in which continuous exposure of rats to bright light leads to retinal cell death and retinal dysfunction. In this model, the expression levels of prolactin receptors in the retina were upregulated. Moreover, retinas from prolactin receptor-deficient mice exhibited photoresponsive dysfunction and gliosis that correlated with decreased levels of retinal bFGF, GDNF, and BDNF. Collectively, these data unveiled prolactin as a retinal trophic factor that may regulate glial-neuronal cell interactions and is a potential therapeutic molecule against retinal degeneration.

Prevalence of conditions causing chronic anovulation and the proposed algorithm for anovulation evaluation.

AIM: This study investigated the prevalence of disease-causing chronic anovulation and proposes a logical investigation flowchart to facilitate diagnosis in women presenting with chronic anovulation. MATERIAL AND METHODS: The cross-sectional retrospective study was performed using 293 reproductive-aged women who were diagnosed with chronic anovulation at the Gynecologic Endocrinology Unit, Faculty of Medicine, Chiang Mai University between January 2008 and December 2012. The demographic data, laboratory investigations and diagnoses were collected. RESULTS: Among 293 patients recruited into the study, the common causes of anovulation were polycystic ovary syndrome (PCOS) (73.4%), prolactin disorder (13.3%) and unexplained chronic anovulation (7.5%). The less common causes were thyroid disorders, congenital adrenal hyperplasia, adrenal tumors and Cushing's disease. There was a strong positive association between the levels of 17-hydroxyprogesterone and/or dehydroepiandrosterone sulfate with the levels of testosterone and androstenedione. The sensitivity and specificity of serum luteinizing hormone to accurately diagnose PCOS were 29.38% and 55.56% (P = 0.03). The luteinizing hormone/follicle-stimulating hormone ratio ≥ 3 had a sensitivity and specificity at 18.56% and 92.86% (P = 0.03) for PCOS diagnosis. CONCLUSION: Serum androstenedione, testosterone, thyroid-stimulating hormone, prolactin levels and pelvic ultrasonography should be included in the initial investigations for anovulation. The 17-hydroxyprogesterone and dehydroepiandrosterone sulfate levels can be used for secondary anovulation evaluations.

[HYPERPROLACTINEMIA AND SELECTIVE SEROTONIN REUPTAKE INHIBITORS. A NARRATIVE REVIEW OF THE LITERATURE]. / Hiperprolactinemia asociada al uso de antidepresivos inhibidores de la recaptación de serotonina. Una revisión narrativa de la literature.

A large number of scientific papers have reported the relationship between the development of hyperprolactinemia and the use of psychotropic drugs, especially the role of antipsychotics which are antidopaminergic drugs. However, less information is known about the role of antidepressants in the development of hyperprolactinemia, specially the selective reuptake inhibitors (SSRIs). The prevalence of hyperprolactinemia as a pharmacological side effect of SSRIs is still unknown, despite the widespread use over the last decade. The aim of this review is to explore the relationship between hyperprolactinemia and SSRIs.

Psychotropic-induced hyperprolactinemia: a clinical review.

BACKGROUND: Psychotropic medications, particularly select antipsychotics, are a common cause of drug-induced hyperprolactinemia. As high prolactin may be associated with hypogonadism, reproductive dysfunction, and bone loss, it is important to recognize this condition and understand its management. OBJECTIVE: The aim of this review is to evaluate the causes, signs, and symptoms associated with hyperprolactinemia, to describe mechanisms through which psychotropic medications elevate prolactin, and to suggest an evidence-based management approach for patients with psychotropic drug-induced hyperprolactinemia. METHODS: A PubMed/MEDLINE search was conducted on the topic of psychotropic agents as a cause of hyperprolactinemia. The material with most relevance to current psychiatric practice and of highest level of evidence was included in this review. CONCLUSION: Hyperprolactinemia should be evaluated in adult patients receiving psychotropic agents if signs and symptoms associated with hyperprolactinemia are present. It is also important to exclude pituitary and hypothalamic disease by magnetic resonance imaging if hyperprolactinemia is not definitely caused by psychotropic medications. As bone loss may occur because of hyperprolactinemia-mediated hypogonadism, bone mineral density (BMD) should be evaluated in patients with persistent high prolactin and reproductive dysfunction. Aripiprazole or other prolactin-sparing atypical antipsychotics may be alternatives or aripiprazole can be considered as adjunctive therapy in select cases of psychotropic-induced hyperprolactinemia.

[Antipsychotic-drug-induced hyperprolactinemia: physiopathology, clinical features and guidance]. / Hyperprolactinémies induites par les antipsychotiques : physiopathologie, clinique et surveillance.

BACKGROUND: Hyperprolactinemia is a frequent but neglected adverse effect observed in patients treated with antipsychotic-drugs. In this review, we summarize its physiopathogenetic mechanism, its clinical manifestations in men and women, and the way to manage it. LITERATURE FINDINGS: Prolactin is a hormone secreted by lactotroph cells in the anterior pituitary. Its synthesis and release are under the control of peptides, steroids and neurotransmitters. The main inhibitory regulation is made by dopamine, which binds dopamine receptors D2 on the membrane of lactotroph cells. Antipsychotic-drugs block these receptors and thus remove the inhibitory effect of dopamine on prolactin secretion. All antipsychotic-drugs block D2 receptors and all can induce hyperprolactinemia. Nonetheless, it seems that the faster the antipsychotic-drug dissociates from D2 receptors, the lesser the increase of prolactin in the plasma. Another way to explain hyperprolactinemia is the ability of antipsychotic-drugs to cross the blood-brain barrier. The role of their metabolites should also be considered. For these reasons, one can distinguish prolactin-raising (conventional neuroleptics, amisulpride, risperidone) and prolactin-sparing (clozapine, aripiprazole, olanzapine) antipsychotics. An English study showed that 18% of men and 47% of women treated with antipsychotics for severe mental illness had a prolactin level above the normal range. Hyperprolactinemia is in fact more frequent in women than in men. Sometimes it is asymptomatic, but the higher the prolactin level is, the more patients have clinical manifestations. Some symptoms are due to the hypogonadism caused by prolactin, which disturbs hypothalamic-pituitary axis function, and others are due to direct effects on target tissues. Consequently, patients can suffer from sexual dysfunction, infertility, amenorrhea, gynecomastia or galactorrhoea. Data suggest that these symptoms are common, but patients don't mention them spontaneously and clinicians underestimate their prevalence. In the long-term, hypogonadism involves a premature bone loss in men and women. Klibanski and colleagues showed that this loss is significant only in women with hyperprolactinemia associated with amenorrhea. That suggests that prolactin is not directly responsible for this clinical feature. Nevertheless, prolactin seems to be involved in the development of breast cancer, but its role is unclear for prostate cancer. DISCUSSION: Our review promotes a check-up before beginning a treatment with antipsychotic agents. First, a baseline prolactin level should be measured. It should also include the research on previous treatment with antipsychotic-drugs and the assessment of adverse effects suggestive of hyperprolactinemia. Questioning should finally look for any contra-indication to antipsychotics. Monitoring during antipsychotic treatment has been studied by a group of international experts in psychiatry, medicine, toxicology and pharmacy who made a critical review of clinical guidance on hyperprolactinemia. Experts notify that it is important to check whether patients have any sexual dysfunction, such as loss of libido or menstrual irregularity, and galactorrhoea. Prolactin level should also be controlled after three months of stable dose treatment, or if any clinical feature of hyperprolactinemia appears. If a patient prescribed antipsychotic-drugs has a confirmed prolactin level above the normal range, it is necessary to exclude other causes of hyperprolactinemia. If antipsychotics are really involved, the management should be adapted with the prolactin level and the patient him/herself. To summarize, clinicians can decrease the dose of the antipsychotic or switch to a prolactin-sparing drug. Oral contraceptives can be added whether to prevent pregnancy or to prevent bone loss and osteoporosis. Finally, experts recommend reserving dopamine agonists to treat antipsychotic-induced hyperprolactinemia in very exceptional circumstances as it can worsen the mental illness.

[Clinical practice guideline for the diagnosis and treatment of hyperprolactinemia]. / Guía de práctica clínica para el diagnóstico y tratamiento de la hiperprolactinemia.

BACKGROUND: Hyperprolactinemia is a common finding within clinical practice in both endocrinology and general practice fields, amongst other specialties. The general practitioner and other specialists must know the indications and serum prolactin determination parameters in order to, once detected, derive the patient for a correct assessment and begin treatment. OBJECTIVE: Formulate a clinical practice guideline evidence-based for the diagnosis and treatment of hyperprolactinemia. METHOD: It took the participation of eight gynecologists, two pathologists and a pharmacologist in the elaboration of this guideline due their experience and clinical judgement. These recommendations were based upon diagnostic criteria and levels of evidence from treatment guidelines previously established, controlled clinical trials and standardized guides for adolescent and adult population with hyperprolactinemia. RESULTS: During the conformation of this guideline each specialist reviewed and updated a specific topic and established the evidence existent over different topics according their field of best clinical expertise, being enriched by the opinion of other experts. At the end, all the evidence and decisions taken were unified in the document presented here. CONCLUSIONS: It is presented the recommendations established by the panel of experts for diagnosis and treatment of patients with high levels of prolactin; also the level of evidence for the diagnosis of hyperprolactinemia, handling drug-induced hyperprolactinemia and prolactinomas in pregnant and non-pregnant patients.

No unfavorable effects on the menstruation recovery of early postoperative hypoprolactinemia after transsphenoidal surgery in patients with lactotroph pituitary neuroendocrine tumor.

OBJECTIVE: Transsphenoidal surgery for lactotroph pituitary neuroendocrine tumor (PitNET) lowers serum prolactin concentrations, occasionally below the normal range. However, the clinical significance of postoperative hypoprolactinemia is still unclear. In this study, we retrospectively reviewed the female patients with lactotroph PitNET who were treated with transsphenoidal surgery to elucidate the influence of postoperative hypoprolactinemia on regular menstruation restoration and endocrinological remission. RESULTS: The serum prolactin levels in all thirty three participating females had decreased following surgery. Serum prolactin levels in seven patients had decreased below the lower limit of normal ranges (hypoproactinemia group) and in the remaining twenty six patients, it was within the normal range (non-hypoproractinemia group). In hypoprolactinemia group, regular menstruation was restored in all patients with only lactotroph axis deficiency. Nine patients from the non-hypoprolactinemia group experienced re-elevation of serum prolactin concentration (27%). No patient in hypoprolactinemia group experienced the relapse of hyperprolactinemia. These data suggest that early postoperative hypoprolactinemia after transsphenoidal surgery for lactotroph PitNET is not only a good predictive factor for endocrinological remission but also no unfavorable effects on regular menstruation restoration.

Prolactin promotes normal liver growth, survival, and regeneration in rodents: effects on hepatic IL-6, suppressor of cytokine signaling-3, and angiogenesis.

Prolactin (PRL) is a potent liver mitogen and proangiogenic hormone. Here, we used hyperprolactinemic rats and PRL receptor-null mice (PRLR(-/-)) to study the effect of PRL on liver growth and angiogenesis before and after partial hepatectomy (PH). Liver-to-body weight ratio (LBW), hepatocyte and sinusoidal endothelial cell (SEC) proliferation, and hepatic expression of VEGF were measured before and after PH in hyperprolactinemic rats, generated by placing two anterior pituitary glands (AP) under the kidney capsule. Also, LBW and hepatic expression of IL-6, as well as suppressor of cytokine signaling-3 (SOCS-3), were evaluated in wild-type and PRLR(-/-) mice before and after PH. Hyperprolactinemia increased the LBW, the proliferation of hepatocytes and SECs, and VEGF hepatic expression. Also, liver regeneration was increased in AP-grafted rats and was accompanied by elevated hepatocyte and SEC proliferation, and VEGF expression compared with nongrafted controls. Lowering circulating PRL levels with CB-154, an inhibitor of AP PRL secretion, prevented AP-induced stimulation of liver growth. Relative to wild-type animals, PRLR(-/-) mice had smaller livers, and soon after PH, they displayed an approximately twofold increased mortality and elevated and reduced hepatic IL-6 and SOCS-3 expression, respectively. However, liver regeneration was improved in surviving PRLR(-/-) mice. PRL stimulates normal liver growth, promotes survival, and regulates liver regeneration by mechanisms that may include hepatic downregulation of IL-6 and upregulation of SOCS-3, increased hepatocyte proliferation, and angiogenesis. PRL contributes to physiological liver growth and has potential clinical utility for ensuring survival and regulating liver mass in diseases, injuries, or surgery of the liver.

Hyperprolactinaemia associated with increased thyroid volume and autoimmune thyroiditis in patients with prolactinoma.

OBJECTIVE: The aim of this investigation was to evaluate the effects of hyperprolactinaemia on thyroid function, volume and nodularity in patients with prolactinoma. CONTEXT: Hyperprolactinaemia has been associated with various autoimmune diseases; however, the data on the correlation between the level of prolactin (PRL) and thyroid disorders have not been adequately clarified. DESIGN: Case-control study. PATIENTS: Forty-eight subjects with new diagnosis of hyperprolactinaemia (group 1) and 39 subjects undergoing treatment for prolactinoma (group 2) were recruited from our outpatient clinic. Fifty-two healthy subjects were included as a control group (group 3). MEASUREMENTS: The serum PRL, thyroid-stimulating hormone (TSH), thyroxine (free T4), thyroidal microsome (anti-TPO) and antithyroglobulin antibodies (TgAb) levels were evaluated, and ultrasonographic thyroid volume was calculated. RESULTS: The frequencies of positive anti-TPO and TgAb were significantly higher in group 1 than in groups 2 and 3 (P = 0·008). Also, the percentage of patients with thyroid heterogeneity were significantly higher in groups 1 and 2 than in group 3 (P < 0·05). The percentage of patients with thyroid nodules were higher in group 1 than in groups 2 and 3 (p1-2 = 0·03, p1-3 = 0·05 and p2-3 = 0·637). The mean thyroid volume was significantly higher in group 1 (P = 0·001), and a positive correlation was found between thyroid volume and the level of PRL (r = 0·616; P = 0·0001). Prolactin had a significant effect on the total volume according to stepwise multiple linear regression analysis (adjusted R(2) is 0·268; P < 0·0001). CONCLUSIONS: Patients with hyperprolactinaemia have significantly increased thyroid volume, thyroid autoimmunity and nodule prevalence.

Is chronic nipple piercing associated with hyperprolactinemia?

Literature on hyperprolactinemia in the setting of a nipple piercing is limited to individuals with concomitant breast/chest wall infection. It is unclear if chronic nipple stimulation from a piercing alone can cause sustained elevations of serum prolactin. Nipple piercing is emerging as a more mainstream societal form of body art, and the answer to this clinical question would potentially alter patient management. Our aim was to assess serum prolactin levels in subjects with nipple piercing. Inclusion criteria were as follows: men and women ≥ 18 years old with nipple piercing(s) present > 6 months. Exclusion criteria included: women who are pregnant, lactating or < 6 months postpartum; subjects on medications known to increase prolactin levels; chest wall/breast infection at the time of phlebotomy or conditions known to be associated with hyperprolactinemia. Three men and eight women were enrolled. Median (range) ages for men and women were 33 (24-42) and 27 years (23-42), respectively. All except one subject had bilateral piercings. The median interval from nipple piercing to blood draw was 4.0 (2.0-12.0) years. None of the subjects had hyperprolactinemia. Median (range) prolactin levels for men and women were 5.6 ng/mL (3.8-7.4) and 8.0 ng/mL (2.8-10.9), respectively. Our results suggest that in the absence of any concomitant infection, chronic nipple piercing is not associated with hyperprolactinemia.

Macroprolactinemia in women with hyperprolactinemia: a 10-year follow-up.

OBJECTIVES: To determine the frequency of macroprolactinemia in a cohort of hyperprolactinemic women, describing 1) the association of macroprolactinemia with clinical variables and morphological changes in the pituitary gland and 2) clinical status and prolactin levels after 10 years of follow-up. DESIGN: Blood samples were obtained from 32 patients for hormonal assessment. Treatment with cabergoline or bromocriptine was interrupted 3 months before the determination of serum prolactin and macroprolactin. Macroprolactin was measured using the polyethylene glycol (PEG) precipitation method. Computed tomography was performed in all patients. RESULTS: The frequency of macroprolactinemia was 28.1%. In 19 patients prolactin remained elevated (persistent hyperprolactinemia). In 13, prolactin returned to normal (former hyperprolactinemia). Nine patients with PEG recovery between 40 and 50%, and the only two macroprolactinemic patients with previous hyperprolactinemia were excluded from the analysis of clinical outcomes. Only one of seven macroprolactinemic patients had an abnormal pituitary image (empty sella). None had galactorrhea. MAIN FINDINGS: Classic symptoms of hyperprolactinemia and abnormal imaging findings are not common in patients in whom macroprolactin is the predominant form of PRL. CONCLUSIONS: Women with hyperprolactinemia, especially if asymptomatic, should be routinely screened for macroprolactinemia. Macroprolactinemia remains stable in the long term.

[Male breast diseases]. / Pathologie du sein de l'homme.

Because andrology is relatively undeveloped in France, the dermatologist is often the doctor first consulted for diseases of the nipple in men. All dermatological diseases can in fact occur at this site. There are some specific nipple diseases such as gynaecomastia, congenital abnormalities, hyperplasia, benign tumours and breast cancer. All clinical examinations and laboratory examinations should focus on diagnosis of this type of cancer and its elimination.

Manifestation of multidrug resistance protein 3 (MRP3) in liver and kidney cells in cholestasis: effects of hyperprolactinemia.

Immunohistochemistry with semiquantitative image analysis showed that cholestasis induced an increase in the manifestation of mrp3 in cholangiocytes of female rats, but did not affect this parameter in the studied structures of kidney. Under conditions of normal liver function, mrp3 expression in cholangiocytes was also elevated during hyperprolactinemia. Expression of mrp3 in cholangiocytes directly correlated with prolactin receptor expression. In cholestasis, prolactin increased mrp3 manifestation of only in the distal renal tubules. Thus, mrp3 manifestation increases in liver cells, but remains unchanged in kidney cells. The hyperprolactinemia-induced changes in the mrp3 levels and their correlations with prolactin receptor expression were shown to differ in the kidney and liver cells. It was hypothesized that prolactin produced a direct effect on mrp3 expression in cholangiocytes.

Prolactin and vasoinhibins: Endogenous players in diabetic retinopathy.

Diabetic retinopathy is a disease of the retinal microvasculature that develops as a complication of diabetes mellitus and constitutes a major cause of blindness in adults of all ages. Diabetic retinopathy is characterized by the loss of capillary cells leading to increased vasopermeability, ischemia, and hypoxia that trigger the excessive formation of new blood vessels in the retina. The influence of the pituitary gland in the pathophysiology of diabetic retinopathy was recognized nearly six decades ago, but the contribution of pituitary hormones to this disease remains unclear. Recent studies have shown that the pituitary hormone prolactin is proteolytically cleaved to vasoinhibins, a family of peptides with potent antivasopermeability, vasoconstrictive, and antiangiogenic actions that can protect the eye against the deleterious effects of the diabetic state. In this review, we summarize what is known about the changes in the circulating levels of prolactin and vasoinhibins during diabetes and diabetic retinopathy as well as the implications of these changes for the development and progression of the disease with particular attention to hyperprolactinemia in pregnancy and postpartum. We discuss the effects of prolactin and vasoinhibins that may impact diabetic retinopathy and suggest these hormones as important targets for therapeutic interventions.