Replication Pattern of Sertoli Cells in Maturing Rat Testis in Vivo and in Organ Culture1

Abstract

The pattern of Sertoli cell replication in maturing rat testes was investigated in vivo and in organ culture, using pulse labeling with ‘H-thymidine and radioautography. The labeling index of Sertoli cells was found to be related to the age of the animals. It was highest in testes of newborn animals and decreased with age, most drastically on day 11. No labeled Sertoli cells were found after postnatal day 15. This pattern appeared to be independent of extragonadal in vivo influences since it was retained in isolated testes grown in organ culture.