Abnormal prolactin levels in serum and seminal plasma in infertile men.

The role of prolactin in male infertility was studied in 33 patients in whom serum and seminal plasma prolactin levels were determined. With the exception of those patients with Klinefelter's syndrome, infertile males presented moderate hyperprolactinemia as compared with a control group of 34 men. Prolactin levels in seminal plasma were greater than in serum in all patients studied; however, prolactin levels in infertile patients were significantly less than in normal males. Therefore, this situation is the reverse of what happens in serum. Seven patients with idiopathic oligospermia were treated with 5 mg of bromocriptine daily during 6 months, resulting in no measurable effect on the sperm count. Infertility in men may be associated with moderate hyperprolactinemia but bromocriptine is of no therapeutic use. Interpretation of the abnormal levels of prolactin in seminal plasma in oligo- and azoospermic men requires further investigation.