Prolactin secretion is regulated by both stimulatory and inhibitory mechanisms. Dopamine acts on pituitary lactotroph D2 receptors to inhibit prolactin secretion while other peptides and hormones, such as thyrotropin releasing hormone (TRH), stimulate prolactin secretion. As a result,<unk>  may be caused by disinhibition (e.g., compression of the pituitary stalk or reduced dopamine levels) or excess production. The most common cause of<unk>  is prolactinoma (a type of pituitary adenoma). A blood serum prolactin level of 1000–5000 mIU/L (47-235 ng/mL) may arise from either mechanism, however levels >5000 mIU/L (>235 ng/mL) is likely due to the activity of an adenoma. Prolactin blood levels are typically correlated to the size the tumors. Pituitary tumors smaller than 10 mm in diameter, or microadenomas, tend to have prolactin levels 1000 ng/mL.<unk>  inhibits the secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus, which in turn inhibits the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the pituitary gland and results in diminished gonadal sex hormone production (termed hypogonadism). This is the cause of many of the symptoms described below. In many people, elevated prolactin levels remain unexplained and may represent a form of hypothalamic–pituitary–adrenal axis dysregulation. Causes of<unk>  Physiologic hypersecretion * Ovulation * Pregnancy * Breastfeeding * Chest wall Injury * Stress * Stress-associated REM Sleep * Exercise Hypothalamic-pituitary stalk damage * Tumors * Craniopharyngioma * Suprasellar pituitary mass * Meningioma * Dysgerminoma * Metastases * Empty sella * Lymphocytic hypophysitis * Adenoma with stalk compression * Granulomas * Rathke's cyst * Irradiation * Trauma * Pituitary stalk section * Suprasellar surgery Pituitary hypersecretion * Prolactinoma * Acromegaly * Laron syndrome Systemic disorders * Chronic kidney failure * Hypothyroidism * Cirrhosis * Pseudocyesis * Epileptic seizures Drug-induced hypersecretion * Dopamine receptor blockers * Atypical antipsychotics: risperidone * Phenothiazines: chlorpromazine, perphenazine * Butyrophenones: haloperidol * Thioxanthenes * Metoclopramide * Dopamine synthesis inhibitors * α-Methyldopa * Catecholamine depletors * Reserpine * Opiates * H2 antagonists * Cimetidine, ranitidine * Tricyclic antidepressants * Amitriptyline, amoxapine * Selective serotonin reuptake inhibitors * Fluoxetine * Calcium channel blockers * Verapamil * Hormones * Estrogens * TRH Physiological causes Physiological (i.e., non-pathological) causes include: ovulation, pregnancy, breastfeeding, chest wall injury, stress, stress-associated REM sleep, and exercise. During pregnancy, prolactin levels can range up to 600 ng/mL, depending on estrogen concentration. At 6 weeks post-birth (postpartum), estradiol concentrations decrease, and prolactin concentrations return to normal even during breastfeeding. Stress-related factors include physical, exercise, hypoglycemia, myocardial infarction, and surgery. Coitus and sleep can also contribute to an increased prolactin release. Medications Prolactin secretion in the pituitary is normally suppressed by the brain chemical dopamine, which binds to dopamine receptors. Drugs that block the effects of dopamine at the pituitary or deplete dopamine stores in the brain may cause the pituitary to secrete prolactin without an inhibitory effect. These drugs include the typical antipsychotics: phenothiazines such as chlorpromazine (Thorazine), and butyrophenones such as haloperidol (Haldol); atypical antipsychotics such as risperidone (Risperdal) and paliperidone (Invega); gastroprokinetic drugs used to treat gastro-esophageal reflux and medication-induced nausea (such as that from chemotherapy): metoclopramide (Reglan) and domperidone; less often, alpha-methyldopa and reserpine, used to control hypertension; and TRH. The use of estrogen-containing oral contraceptives are also known to increase prolactin levels when taken in high doses >35 μg. The sleep drug ramelteon (Rozerem) also increases the risk of<unk> . Particularly, the dopamine antagonists metoclopramide and domperidone are both powerful prolactin stimulators and have been used to stimulate breast milk secretion for decades. However, since prolactin is antagonized by dopamine and the body depends on the two being in balance, the risk of prolactin stimulation is generally present with all drugs that deplete dopamine, either directly or as a rebound effect. Specific diseases Prolactinoma or other tumors arising in or near the pituitary — such as those that cause acromegaly may block the flow of dopamine from the brain to the prolactin-secreting cells, likewise, division of the pituitary stalk or hypothalamic disease. Other causes include chronic kidney failure, hypothyroidism, bronchogenic carcinoma and sarcoidosis. Some women with polycystic ovary syndrome may have mildly-elevated prolactin levels. Nonpuerperal mastitis may induce transient<unk>  (neurogenic<unk>  of about three weeks' duration; conversely,<unk>  may contribute to nonpuerperal mastitis. Apart from diagnosing<unk>  and hypopituitarism, prolactin levels are often checked by physicians in those who have suffered a seizure, when there is need to differentiate between epileptic seizure or a non-epileptic seizure. Shortly after epileptic seizures, prolactin levels often rise, whereas they are normal in non-epileptic seizures.
Hyperprolactinaemia
Polycystic ovary syndrome
Hyperproinsulinemia
Hyperinsulinemia
Oxyhyperglycemia
Hyperprolinemia
Hypoglycemia
Hyperinsulinism