USEFULNESS OF THYROTROPIN-RELEASING-HORMONE TEST, SMS-201-995, AND BROMOCRIPTINE IN THE DIAGNOSIS AND TREATMENT OF GONADOTROPIN-SECRETING PITUITARY-ADENOMAS

Five patients with gonadotropin-secreting pituitary adenomas were stud ied. The utility of gonadotropin response to TRH stimulation in the di agnosis and follow-up of these tumors was evaluated, as well as the ef fects of somatostatin analogue SMS 201-995 and bromocriptine on gonado tropin release. Three patients had FSH and LH secreting adenomas while the other two tumors secreted FSH and a-subunit. Transsphenoidal rese ction of the pituitary adenomas were performed in all patients. Follow ing preoperative TRH administration (400 mu g iv), marked increases we re observed in FSH levels in two cases, in LH levels in three and in a -subunit in one. The FSH and LH responses to this stimulus persisted i n the same patients after. surgery. Following acute bromocriptine admi nistration (5 mg orally), FSH was reduced in all cases by 19% to 46%, LH in three cases by 50-67% and alpha-subunit in one by 33%. In patien t no. 5, with persistent high FSH levels in the immediate postoperativ e period, long-term bromocriptine treatment was administered (15 mg/d orally), resulting in normalization of FSH levels 6 months later, alth ough the size of the tumor was not reduced. After acute SMS 201-995 ad ministration (100 mu g sc) FSH decreased in two cases by 38% and 76%, LH in three by 30-56% and a-subunit in one by 20%. We conclude that go nadotropin response to TRH stimulation is useful in the diagnosis and follow-up of patients with gonadotroph adenoma. Bromocriptine and SMS 201-995 may be effective as coadjuvant treatment following surgery and radiotherapy in these patients, although long-term studies will be ne cessary to confirm these proposals.