164 THE SIGNIFICANCE OF POSTNATAL GONADOTROPHIN SURGE FOR TESTICULAR DEVELOPMENT IN NORMAL AND CRYPTORCHID TESTIS

Abstract

The hormonal and histological findings in cryptorchidism led us to investigate the following theory: The postnatal FSH and LH increase is not only responsible for setting of the gonadostat but a major pre-requisit for an adequate testicular development for later fertility. Testicular biopsies (36th week of pregnancy to 9 months postnatally) have been investigated from 29 cryptorchid infants operated without prior hormone treatment and compared to 34 biopsies of normal testes (9 post mortem, 25 biopsies because of suspected testicular damage during surgery for hydrocele or inguinal hernia). The absolute and relative number of spermatogonia increased from 50 to 100 per 50 tubuli in normally descended testes. In cryptorchid testes, however, the number of spermatogonia remained low and did not increase with age. In contrast, the total number of germ cells was always comparable in both groups. This gives evidence for a lack of transformation of gonocytes into spermatogonia in cryptorchid testes, which furthermore showed in contrast to normal testes no increase in the number of Leydig cells. The postnatal development of Leydig cells and the transformation from gonocytes into spermatogonia parallels the LH and FSH increase in the first few months of life. The activation of the gonadotrophin-gonadal axis could thus not only be responsible for the “setting” of the gonadostat but a pre-requisit for an adequate testicular development.