Successful gonadotrophin treatment of hypogonadism in postoperative patients with macroprolactinoma and persistent hyperprolactinaemia

Abstract

We report on two males with prolactinoma in whom hyperprolactinaemia and hypogonadism persisted for several years postoperatively despite the administration of a dopamine agonist or bromocriptine. In these patients, a GnRH test revealed no response in the levels of serum LH or FSH. An hCG stimulation test provoked no response in the serum levels of testosterone. Case 1, who was 28 years old at the first visit, received parenteral testosterone and appreciable virilization of the genitalia was noted within a few months. When he married and desired to father a child, the treatment was switched to hCG/hMG combined therapy and spermatozoa appeared subsequently in the ejaculate, although their numbers were low. His wife conceived and delivered a healthy baby girl. Case 2 was a single young man who presented with hypogonadotrophic hypogonadism and hyperprolactinaemia. He was started on hCG injections three times per week and the maturation of his genitalia was advanced rapidly. Semen analyses showed sperm concentration and motility to be within the normal range. Post-treatment GnRH test revealed no improvement in gonadotrophin responses for LH or FSH. In both cases, the hCG test repeated after the gonadotrophin treatment showed normal basal and stimulated testosterone levels. During the course of gonadotrophin treatment in these cases, serum prolactin levels remained elevated, and it is suggested that, in the two cases, the hypothalamo-pituitary function was disturbed by the tumour or its manipulation and the capacity of the pituitary gland to secrete gonadotrophin was impaired. Under such circumstances with persisting hyperprolactinaemia, hCG and/or hCG/hMG combination treatment can induce normal virilization and advance spermatogenesis sufficiently to achieve fertility.

American Association of Clinical Endocrinologists Medical Guidelines for Clinical Practice for the Evaluation and Treatment of Hypogonadism in Adult Male Patients—2002 Update

“…Medical therapy with bromocriptine, pergolide, or cabergoline may effectively reduce prolactin levels sufficiently to allow gonadal function to resume or allow stimulation with gonadotropins. Even when prolactin levels cannot be normalized, hCG therapy alone or in conjunction with human menopausal gonadotropin (or FSH) therapy may stimulate spermatogenesis in treated prolactinomas and result in pregnancies (77).…”

Experimental hyperprolactinemia in a rat model: alteration in centrally mediated neuroerectile mechanisms

“…53 As the LH and FSH response to exogenous GnRH is frequently normal or frankly excessive in these patients suggesting a normal pituitary gonadotrophin reserve, the defect is likely to reside in the hypothalamus and is generally thought to be a functional and potentially reversible alteration in GnRH secretion. 54 Severe hyperprolactinemia (prolactin b 2000 mUal) may cause hypogonadism and is almost invariably associated with sexual dysfunction in the male.…”