[Spermatogenesis after testosterone supplementation in the hypophysectomized ram].

Six adult rams were hypophysectomized and immediately injected with 0,5 g (group A) or 2 g (group B) of testosterone per day for 2 weeks. Three normal rams (group C) received the solvent only. The testosterone concentrations in the testis (ng/g) were the same in groups A (23 +/- 7) and C (22 +/- 4) and 3 times higher in group B (72 +/- 18). There was an uptake of testosterone by the testis of the two supplemented groups. In the Rete Testis Fluid, the testosterone concentration was normal with 0,5 g/day (29 +/- 0.6 ng/ml). The testicular weight was maintained by the two treatments. However, spermatogenesis was abnormal in both supplemented groups; meiosis and spermiogenesis occurred normally, but the efficiency of spermatogonial divisions, as shown by the number of leptotene and zygotene primary spermatocytes, was greatly reduced (85%). The results indicate that testosterone alone in the Ram is unable to support complete spermatogenesis, which is contrary to that found in the Rat.