Effects of oestrogen and androgen on the sexual behaviour responses of the ovariectomized ewe.

Abstract

The secretion of gonadal steroid hormones that stimulate sexual behavior differs between males and females in 2 respects: the hormones are chemically different, estrogen and progesterone on 1 hand and androgen on the other, and their pattern of release into the blood stream differs according to the sex of the animal. Those produced by the female are released during a limited period whereas testosterone exhibits little day-to-day variation. 12 ovariectomized Ile-de-France ewes were injected either with 50 mg of estradiol benzoate of 10 mg or testosterone propionate 48 hours after the last of 5 daily injections of 25 mg of progesterone. In both cases the experimental females exhibited normal female sexual behavior. In a 2nd experiment, the ewes were injected daily for 4 weeks either with 50 mg of estradiol benzoate or with 10 mg of testosterone propionate. In both cases male patterns of sexual behavior appeared, but more intensely with androgen than with estrogen, and simultaneously, the ewes became receptive. However, receptivity declined rapidly after a few days of estrogen treatment. This decline did not occur with androgen.