Further observations on the early events that contribute to establishing the morphological pattern shown by the oestradiol suppressed testis

The analysis of the morphological response of the seminiferous epithelium to hormone suppression after hypophysectomy has been widely used in the study of spermatogenesis, Unlike hypophysectomy, which causes a sharp fall in gonadotropin levels, oestradiol treatment, although mimicking its effects, leads to a partial and progressive hormone suppression. We have chosen this model in order to clarify further the early morphological response of the seminiferous epithelium to hormone suppression, For this purpose, adult male rats, injected daily from 1-35 days with 50 mu g oestradiol benzoate, were analyzed. Our observations showed that cell sloughing was the main cause of germ cell depletion in the oestradiol treated testis, After 17-18 days treatment, massive sloughing affected nearly all the germinal cells, but the correct synchronization of mitoses, meiosis and spermatid differentiation along the 14 stages of spermatogenesis was always well kept. Quantitative analysis showed that spermatogenic wave was well preserved in the oestradiol-treated animals and that sloughing was a stage-independent phenomenon.