Gonadotropin and androgen levels in patients operated upon for cryptorchidism.

53 patients previously operated upon for cryptorchidism were examined seven years (range 2-18) after the operation. We measured serum levels of sex-hormone-binding-globulin (SHBG), testosterone (T), free testosterone (free T), dihydrotestosterone (DHT), 4 androstenedione (4-AD), and dehydroepiandrosteronesulphate (DHAS), and the gonadotropin luteinizing hormone (LH) and follicular hormone stimulating (FSH). Compared to normal controls, there were decreased levels of free testosterone and DHT and increased levels of SHBG and DHAS. The FSH levels were elevated and LH values low. No relationship was found between androgen and gonadotropin levels, suggesting that the normal feed-back mechanism is malfunctioning. There were no hormonal differences between patients with previous unilateral and bilateral cryptorchidism, although SHBG levels were higher in the former. We concluded that cryptorchidism is probably due to a defect in the hypothalamic-pituitary axis and not to a primary defect in the testes.