THE ROLE OF THE TESTIS IN THE RELEASE OF GONADOTROPHINS FROM THE HYPOPHYSIS

Abstract

To study the role of the spermatogenic epithelium and of the interstitial cells of Leydig.in the release of the pituitary gonadotrophins, groups of normal, cryptorchid and castrated adult rats were joined parabiotically to immature male and female rats for a period of seven days. On examination of the genital organs of different recipients, it has been concluded that: (1) In normal rats, there is no appreciable release of any gonadotrophin during the short period of parabiosis. (2) The spermatogenic epithelium inhibits the release of FSH, while the interstitial cells liberate a hormone that inhibits the release of ICSH. (3) Release of the gonadotrophin which causes luteinisation of the granulosa cells is not activated by cryptorchidism or castration. This gonadotrophin is different from the one responsible for stimulation of growth and functional activity of the Leydig cells. The term "LH" is better confined to the former and "ICSH" to the latter gonadotrophin. (4) ICSH not only acts on the testis but also on the ovary and indirectly on the uterus; this action has been discussed.