Endocrine studies in patients with isolated gonadotrophin-releasing hormone deficiency.

Twelve black women with isolated gonadotrophin deficiency were studied. After administration of intravenous gonadotrophin-releasing hormone (GnRH), all patients had subnormal gonadotrophin responses. However, after priming with subcutaneous GnRH (in 9 patients) follicle-stimulating hormone responses improved in 4 patients and luteinizing hormone responses in 7 patients. Prolactin responses to intravenous thyrotrophin-releasing hormone were significantly decreased at 20 and 60 minutes, when compared with reference subjects (P less than 0.01). In response to insulin-induced hypoglycaemia, prolactin responses were heterogeneous in 11 patients, while those of growth hormone were suboptimal in 8 of the 11 patients tested.