Hyperprolactinemia and sexual function in men: a short review

Erectile dysfunction (ED), generally associated with reduced sexual desire and sometimes with orgasmic or ejaculatory dysfunction, is the major revealing symptom of hyperprolactinemia (HPRL) in men, a condition that should not be neglected since many cases result from pituitary tumors, likely to result in serious complications. It is generally believed that the mechanism of the prolactin (PRL)-induced sexual dysfunctions is a decrease in testosterone secretion. In fact, serum testosterone is normal in many hyperprolactinemic males and there are also testosterone-independent mechanisms, probably mainly set at the level of the brain's neurotransmittor systems. Systematic determinations of serum PRL found very low prevalences of marked HPRL (>35 ng/ml) in ED patients (0.76% in a compilation of over 3200 patients) as well as of pituitary adenomas (0.4%). In addition, the association of HPRL with ED may have been coincidental in some of these cases, since 10% of the HPRLs diagnosed by the usual immunological assays are composed of macroprolactins, which are biologically inactive or little active variants of PRL. Their identification requires a PRL chromatography that is restricted to some specialized laboratories. There is presently no consensus with regards to the screening for HPRL in ED: systematic determination of serum PRL may be justified since HPRL is a serious but reversible disease, while there is presently no reliable clinical, psychometric or hormonal criteria (including serum testosterone level) allowing to restrict its determination to certain categories of the ED patients without risk of neglecting some HPRLs. In case of consistent HPRL, searching for a hypothalamic or pituitary tumor is mandatory. Dopamine-agonist therapy is the first choice treatment for the PRL-induced sexual dysfunctions. Additional sexual counselling may be necessary for certain patients.