Numerous investigators1 recently have reported favorable results in the treatment of undescended testes with gonadotropic substance. There has arisen a good deal of justifiable skepticism, however, as regards the value of this form of treatment in unselected cases. Where there is a mechanical factor preventing the normal descent of the testes the administration of gonadotropic substance cannot be expected to bring them down.
Engle2 has brought forward evidence as to the hormonic nature of the factors controlling the natal descent of the testes in the human being. That the gonads in turn influence the functional activity of the hypophysis has been shown by Nelson.3 This worker has reported that, as the testes of rats which are rendered cryptorchid undergo retrogressive changes, the hypophysis in these animals exhibits changes similar to those found after castration. The injection of gonadotropic factor from pregnancy urine (antuitrin-S) into these animals results in the stimulation and restoration of the seminal vesicles and prostates, while the hypophysis shows a disappearance of the castration cells. There is no change in the epithelium of the seminiferous tubules but there is a marked stimulation of the interstitial tissue of the testes. The treatment of a series of castrate rats with gonadotropic factor extracted from pregnancy urine resulted in no change in the hypophysis and sex accessories. Nelson believes that the testes play an intermediary rôle in the influence exerted on the pituitary and sex accessories. This may be exerted by the secretion of the testis hormone or by estrogen, either secreted directly by the testis or converted from the testis hormone.