Medical causes and consequences of hyperprolactinaemia. A context for psychiatrists

Abstract

Hyperprolactinaemia is the commonest endocrine disorder of the hypothalamic-pituitary axis and can lead to both short-term sexual dysfunction and galactorrhoea, and long-term loss of bone mineral density. Prolactin is secreted from the anterior pituitary gland under the influence of dopamine, which exerts a tonic inhibitory effect on prolactin secretion. Physiological regulators of prolactin secretion include many different types of 'stress' and sleep. Disruption of the normal control of prolactin secretion results in hyperprolactinaemia from pathological and pharmacological causes. The administration of antipsychotic medication is responsible for the high prevalence of hyperprolactinaemia in people with severe mental illness. Physiological hyperprolactinaemia, such as pregnancy and lactation, should be distinguished from pathological causes to prevent unnecessary investigation and treatment. The causes, consequences and management of hyperprolactinaemia are discussed in this article.

Bromocriptine Treatment for Inappropriate Lactation in Mares: A Case Report

“…mediated by TRH, vasoactive intestinal peptide, and prolactin-releasing peptide [30]. The connections between the hypothalamus and pituitary are critical in maintaining the physiological secretion of prolactin, and any malfunction of the pituitary leads to the loss of inhibition by dopamine and consequent hyperprolactinemia [3,32].…”

“…Hyperprolactinemia is a common disorder of the hypothalamic-pituitary axis, which usually presents with reproductive abnormalities [2,3]; it may be caused by pituitary tumors, hypothyroidism, or secondary effects of drugs [1,4].…”

Prolactin and Schizophrenia, an Evolving Relationship

“…In general terms, prolactin levels <2000 mIU/L may be due to a medication effect but other causes can include microprolactinoma, pituitary stalk compression, renal failure or hypothyroidism (Holt, 2008). The literature currently reports that macroprolactinomas are the most common cause of prolactin levels >2120 mIU/L in the general population ) although other authors propose higher levels (3180 mIU/L) at which hyperprolactinaemia can be assumed to be caused by a macroprolactinoma (Holt, 2008). When evaluating hyperprolactinaemia it is also critical to understand the incidence or prevalence of hyperprolactinaemia from the patient perspective as opposed to a mean level from a cohort.…”

“…Prolactin is released from the anterior pituitary in a pulsatile manner and has a half life of around 50 minutes (Citrome, 2008). It peaks around 10 times per day in young adults (Holt, 2008) with a marked circadian rhythm highest during sleep and reaching a nadir during waking hours. Time of measurement is thus important to standardise and is best undertaken before drug dosing in a fasting state in the morning, although this is not always pragmatic in schizophrenia due to the nature of the illness.…”

“…Other confounders are much better recognised with a study of 154 schizophrenia patients taking 6mg risperidone reporting that prolactin levels correlate with gender (higher in females), age (lower in older patients) and smoking status (p<0.01) based on a multiple regression analysis (Ohta et al, 2011). Control of prolactin secretion from the anterior pituitary is predominantly under the control of dopamine released via hypothalamic dopaminergic neurons, the tuberoinfundibular and tuberohypophyseal dopaminergic neurones (Holt, 2008). Dopamine is transported from the hypothalamus to the anterior pituitary via the long hypophyseal portal vessels and inhibits the high basal secretory tone of the lactotroph.…”