Cardiometabolic effects of hypoprolactinemia

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