Index of articles, click here.
Abnormal prolactin secretion in men and women
By Serge Kreutz
Ljubljana, 4. August 2010
Despite the advances that are cited to account for the expanding knowledge of prolactin secretion in women, normal and abnormal prolactin secretion in men continues to be a mystery. The physiological role of prolactin in men is unknown, but hyperprolactinemia is associated with a characteristic if rare endocrine syndrome. As of now, less than 100 cases have been carefully described. Yet, despite its rarity, the condition is important because the associated symptomatology is highly distressing and readily curable. To characterize the syndrome, a group of 29 men specifically selected because they had hyperprolactinemia and pituitary tumors were studied some years ago. Many of these patients had very long histories of their presenting complaints. Most had large pituitary tumors, and in 20 of the 26 who had lumbar air encephalography there was evidence of supra sellar extension. The clinical features mainly concerned the reproductive system. 17 complained of complete lack of libido and impotence and 6 complained of impaired libido and potency. Several gave a history of long term psychiatric treatment for sexual dysfunction and divorce and unhappy marriages were common. On examination there were often features of hypogonadism and the association of gynecomastia with small testicles had on occasion initially suggested a diagnosis of Klinefelter's syndrome. Endocrine investigation produced the following results: there was a clear association of impotence with the degree of hyperprolactinemia and the extent of suppression of testosterone secretion. Plasma testosterone concentrations were usually below normal in the impotent men and in some were actually in the prepubertal range. Despite this profound testosterone deficiency, the plasma concentrations of luteinizing hormone (and of follicle stimulating hormone) and their response to gonadotrophin releasing hormone were usually in the normal range. In regard to management, it is hoped that earlier recognition will improve the outcome and that anatomical regression of large pituitary tumors can be achieved by treatment with bromocriptine alone without the risks of hypopituitarism. In women the hyperprolactinemic syndrome is usually associated with amenorrhea. Symptomatically it is usually dominated by the consequences of estrogen deficiency, so that complaints of dyspareunia and dryness during intercourse are common. Libido is often lost. Galactorrhea is unusual. Some women with hyperprolactinemia have anovulatory menstrual cycles or impaired luteal phases. Hyperprolactinemia accounts for 20% of cases of amenorrhea. 40% of cases have pituitary tumors and about 10% of the pituitary tumor cases have supra sellar extension. Recently the long term outcome of treatment of hyperprolactinemia was studied. It was found that 14 of 36 cases of hyperprolactinemia that were treated by suppression of excessive secretion were "cured," that is, after discontinuing bromocriptine they maintained their ovulation cycles and had normal serum concentrations of prolactin. The only feature predictive of a cure was the pretreatment serum prolactin concentration.