Androgen effects on Sertoli cells

Mature male rats, gamma-irradiated in utero, were hypophysectomized. In an effort to maintain the seminiferous epithelium, some animals were treated with exogenous androgen while in other animals the seminiferous epithelium was allowed to regress without hormonal treatment. These Sertoli cell-enriched (SCE) males were evaluated for 7 weeks following hypophysectomy. In SCE males the average initial weight of each testis was 300 mg which declined to 110 mg at 7 weeks post-hypophysectomy. Concomitantly, seminiferous tubule diameter decreased from 130 microns to approximately 89 microns. Numerous cells were detached from the lamina propria and were observed in the centre of the tubule. Two layers of Sertoli cell nuclei were frequently observed in the regressed seminiferous tubules. Many of these nuclei appeared to be less differentiated, i.e. the nuclei were smaller with smaller nucleoli and more heterochromatin. In contrast, hypophysectomized animals treated with testosterone propionate during the last 5 weeks of the 7 week observational period, retained a tissue weight of about 270 mg/testis (a 5-10% decline in weight compared with normal untreated controls). Also, these animals had seminiferous tubule diameters of 132 microns. Finally, the Sertoli cells which comprised primarily a single layer inside the seminiferous tubules had larger nuclei with finely granulated chromatin and large nucleoli. Protein changes in SCE testes, (+/-) androgen, following hypophysectomy were analysed using polyacrylamide gels containing SDS. Prominent changes in the protein profile as separated by molecular weight were observed and were attributable to androgen stimulation. These changes were probably occurring in Sertoli cells since the Sertoli cell represents about 70% of the total cell population in the gamma-irradiated model. It is concluded that testosterone is responsible for major changes in mature Sertoli cells, although potential contributions of other cell types such as myoid cells and Leydig cells are considered.