Dissociation of prolactin responsiveness to TRH and chlorpromazine in women with isolated gonadotropin deficiency.

The hormonal response to luteinizing hormone releasing hormone (LHRH) thyrotropin releasing hormone (TRH) and chlorpromazine has been evaluated in eleven female subjects with the syndrome of isolated bihormonal gonadotropin deficiency (IGD). Following LHRH, all subjects had elevations of both LH and FSH, but the gonadotropin responses were attenuated relative to those observed in normal female subjects studied in the early proliferative phase of the cycle. Similarly, peak TSH levels after TRH were significantly less in subjects with IGD relative to normal controls. Basal prolactin levels were low in the patient group. Prolactin levels following TRH increased at least two-fold in control subjects and in the group with IGD. Conversely, chlorpromazine failed to induce elevations of prolactin in eight of nine females with IGD.