The significance of postnatal gonadotropin surge for testicular development in normal and cryptorchid testes.

Testicular biopsies from 29 infants with cryptorchidism between birth (gestational age as early as 36 weeks) and 9 months of age were compared to 34 biopsies from the testes of boys at postmortem examination, or during operation for a hydrocele or hernia. The total number of germ cells was similar in both groups but normal testes showed a transformation of gonocytes into spermatogonia to an extent that was not seen in the cryptorchid testes. Cryptorchid testes also showed markedly reduced numbers of Leydig cells compared to normal. These postnatal changes occurred in the normal testes at the same time that the increase is seen in luteinizing and follicle-stimulating hormones during the first few months of life and they are believed to be a consequence of this hormonal activity. It is postulated that the postnatal surge of gonadotropins may be responsible for priming the testes for subsequent development and fertility.