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Induction of Ossification in the Clitoris of Neonatal Female Rats by Administration of Androgens

1980; Oxford University Press; Volume: 106; Issue: 6 Linguagem: Inglês

10.1210/endo-106-6-1956

1945-7170

Hiroki Yoshida, Charles Huggins,

Sexual function and dysfunction studies

The effects of a single injection of sex steroids in neonatal female Sprague-Dawley rats on the development of os clitoris were studied. Os clitoris was not detected in neonatally intact control female rats at 28 days of age but was seen in 100% of neonatally androgen-injected ovariectomized or nonovariectomized rats at 28 days of age. Testosterone propionate (1 mg) or 5a-dihydrotestosterone (1 mg) was injected sc within 24 h after birth. On the contrary, single injections of progesterone (1 mg) and 17β-estradiol (0.1 mg) in female rats had no effects. Histological studies of the clitoris in female rats treated with testosterone propionate revealed the aggregation of immature stromal cells at 3 days of age, the appearance of homogenous eosinophilic interstitial substance in the intercellular spaces at 7 days of age, the development of hyalin cartilage at 14 days of age, and the formation of bone with cavity at 21 days of age. These results indicate that the initiation of bone formation in the clitoris is dependent on androgens, and that the mode of the ossification of the androgen-induced os clitoris is endochondral. Rates of induction of os clitoris by the injection of various amounts of testosterone propionate in neonatal female rats were as follows: 1000 jug, 100%; 100 μg, 100%; 10 jug, 93.3%; 1 jug, 14.3%; and 0.1 μg, 0%. A single injection of 1.0 mg testosterone propionate to female rats at 0, 1, 2, or 7 days of age resulted in the induction of os clitoris, and the incidences were 100%, 100%, 100%, and 77.8%, respectively. Os clitoris was not detected in any rats treated with 1.0 mg testosterone propionate at 10 days of age. These results show that androgen treatment causes the stromal cells in the clitoris to form os clitoris and that the sensitivity to androgens is maintained for 7 days after birth. (Endocrinology106: 1956, 1980)