PUBERTAL INCREASE IN RESPONSIVENESS TO ANDROGEN IN THE MALE RAT

Publisher Website
Google Scholar
Abstract
In the colony of rats used, spermatogenesis becomes complete at approx. 40 days of age. The seminal vesicles at 10, 20 and 30 days exhibit a histology essentially that of the castrated adult animal. At 40 days the growth rate of the seminal vesicles increases sharply, the epithelium revealing beginning response to androgen, consisting of heightening of the epithelium, appearance of secretion granules, and mitoses. By 60 days the seminal vesicles are histologically fully mature. The minimum effective dose of testosterone was detd. at ages 10, 20, 30, 40, 50, 60, 80, 100, and 120 days in [male] rats castrated at birth. At 10 and 20 days the smallest dose eliciting recognizable response in the seminal vesicles was 30 [mu]g. and at 30 days 25 [mu]g., whereas at 40, 50, and 60 days 5 [mu]g. was effective. The threshold rose to 25 [mu]g. at 80,100 and 120 days. Thus the rat castrated at birth exhibits greatest responsiveness to injected testosterone at the age at which the accessory organs of reproduction normally undergo their most profound alteration.