The responses to synthetic luteinizing hormone-releasing hormone in patients with primary selective pituitary deficiency in gonadotropins

Fifteen patients, 11 female and four male, with primary selective pituitary deficiency in gonadotropins were submitted to the subcutaneous administration of 100 to 400 mcg. of luteinizing hormone-releasing hormone (LH-RH). When compared to the effect of LH-RH in eight normal female subjects, two types of responses were observed: there were either small increments in both luteinizing hormone (LH) and follicle-stimulating hormone (FSH) or increases comparable to those observed in normal subjects. Five patients received 100 mcg. of LH-RH daily over four consecutive days. No additive nor depleting effects could be observed. The responses in seven patients given 400 mcg. were not significantly different from those obtained with 100 mcg. Our results indicate two possible etiologies of primary hypogonadotropic hypogonadism. A normal response in LH and FSH after administration of LH-RH assesses a selective hypothalamic deficit in releasing hormones, whereas a negative or low response suggests a dysfunction of the pituitary gonadotropic cell.