Gonadotrophin stimulation in children with abnormal sexual development.

Plasma levels of testosterone were measured by radioimmunoassay before and after 3 days' administration of human chorionic gonadotrophin (HCG) 2,000 IU/d in 34 prepubertal boys (6 normal, 3 with anorchia, 5 with micropenis, 8 with cryptorchidism, 6 with hypogonadotrophic hypogonadism and 6 with hypospadias). The increase in plasma testosterone value ranged from 2.4 nmol/l to 10.5 nmol/l in normal boys. There was negligible (P greater than 0.05) response in boys with anorchia compared with normal children. Subjects with micropenis showed subnormal response (P greater than 0.05). Children with cryptorchidism showed a normal increase in testosterone levels (P greater than 0.05), but in those with hypogonadotrophic hypogonadism and hypospadias the increase was variable (1.2 - 8.8 nmol/l) (P greater than 0.05). Although the HCG stimulation test is not diagnostic in the majority of the sexual disorders, it appears to be sensitive for diagnosing anorchia.