Gonadotrophin therapy is utilised to establish or restore fertility in patients with gonadotrophin deficiency of all causes. Two gonadotrophin preparations are available: human menopausal gonadotrophins (hMG) and hCG: hMG contains 75iu. FSH and 75iu LH per vial, while hCG has little FSH activity and resembles LH in its ability to stimulate testosterone production by Leydig cells Due to the expense of hMG, treatment is usually initiated with hCC alone, and hMG is added later to stimulate the FSH-dependem stages of spermatid development. A high ratio of LH to FSH activity and a long duration of treatment (three to six months), are necessary to bring about the maturation of the prepubertal testis. Once spermatogenesis is restored in hypophysectomised patients or initiated in hypogonadotrophic hypogonadal men by combined therapy, it can usually be maintained with hCG alone.
