[Comparison between the influence of estradiol benzoate, testosterone propionate and human chorionic gonadotropin on initiation of spermatogenesis in the rat].

Newborn male rats were injected daily from the 5th to 15th day of life with: EB in doses of 6.2 or 12.5 or 25.0 micrograms and TP in doses of 1.2 or 2.5 or 5.0 mg (experiment 1), and with hCG (experiment 2) in doses of 2.0 or 4.0 or 8.0 I.U. Animals were sacrificed on the 16th day of life, testes and seminal vesicles were taken and fixed. The function of seminiferous tubules was examined by quantitative analysis of spermatogenesis. EB increased the mean number of germinal cells. TP stimulated differentiation of spermatogonia, but it decreased the number of all germinal cell types. Only the lowest dose of hCG stimulated the mean number of germ cells in the earliest stages of spermatogenesis, hCG used in the higher doses suppresses maturation of seminal tubules and decreases testicular weight.