Lack of gonadotropin secretion in GnRH deficiency

Serum LH (blue) and FSH (red) concentrations determined at 10-minute intervals in 2 males with idiopathic hypogonadotropic hypogonadism. Patient A (panel A) had microphallus, testicular volumes of one mL each, anosmia, and no history of spontaneous puberty. LH and FSH concentrations in most of their serum samples were at or below assay detection limits. Patient B (panel B) had a normal-sized phallus, testicular volumes of 20 mL each, an intact sense of smell, and a history of partial onset of puberty with subsequent regression of sexual function. Serum testosterone concentrations (in ng/dL) at 6-hour intervals are indicated by the numbers at the top of each sampling period.