Recent advances in the understanding of the pathophysiology and treatment of hyperprolactinemia

Hyperprolactinemia is frequently diagnosed in patients with infertility and menstrual cycle irregularities. Control of prolactin secretion is complex and involves inhibition by dopamine and possibly endothelins, as well as stimulation by serotoninergic and opioidergic pathways, gonadotropin-releasing hormone, and possibly galanin. Some patients with hyperprolactinemia have underlying functional disorders, but by using magnetic resonance imaging, a microprolactinoma can be found in most. Prolactin circulates in a low-bioactivity glycosylated and a nonglycosylated form, and an antibody-bound form is found in a few hyperprolactinemic patients who are relatively asymptomatic. The majority of patients, particularly those with macroprolactinomas, will benefit from treatment with bromocriptine. Available alternatives for intolerant patients include vaginal administration of bromocriptine and pergolide mesylate. Other compounds, monthly injectable and slow-release forms of bromocriptine, quinagolide and carbegoline, are not yet available in the United States. Withdrawal of treatment during pregnancy is still recommended, with a low risk of tumor enlargement, and the need for life-long treatment is now being reconsidered.