Androgen-Induced Precocious Puberty in the Female Rat and Its Inhibition by Hippocampal Lesions

Abstract

Precocious puberty is induced in the female rat by treatment with 0.1 mg testosterone propionate on days 17 and 19, 21 and 23, or 25 and 27 of age, or by treatment with 0.05 mg at 21, 23 and 25 days of age. Such rats show early vaginal opening and early onset of first estrus, followed by regular estrous cycles. The effect of testosterone propionate on the vaginal opening seems to be due to a peripheral action of the hormone. Females castrated at 21 days of age and treated with 0.1 mg of testosterone propionate at 21 and 23 days of age show vaginal opening at the same time as the intactanimals. Perivaginal injection of 0.01 mg of testosterone propionate at 21 and 23 days of age causes an early vaginal opening in intact animals without advancing the onset of the first estrus. Early onset of first estrus and an early initiation of estrous cycles appear to be due to central effects of testosterone propionate bringing about an advancement of the maturation of the hypothalamic- pituitary-ovarian axis. The central effects of testosterone propionate can be blocked by lesion to the anterior ventrolateral hippocampus. (Endocrinology84: 14, 1969)