THE EFFECT OF MIROESTROL ON VAGINAL CORNIFICATION, PITUITARY FUNCTION AND PREGNANCY IN THE RAT

Publisher Website
Google Scholar
Abstract
SUMMARY: 1. The effectiveness of miroestrol in causing cornification of the vagina of the ovariectomized rat, inhibiting pituitary activity of the adult male rat and preventing pregnancy in the mated female rat has been compared with that of hexoestrol and stilboestrol when each oestrogen is administered either subcutaneously or orally. 2. Inhibition of pituitary function and prevention of pregnancy by these substances are directly related to their activity in producing cornification of the vaginal epithelium. Only large doses of oestrogen produce the first two responses fully. 3. When administered subcutaneously miroestrol has about 0·3 of the potency of stilboestrol and 0·25 of that of hexoestrol in each response studied. By oral administration it is 0·8 as potent as stilboestrol and more potent than hexoestrol. Since the potency of miroestrol compared with a given oestrogen administered in the same way is of the same order in each response, it is concluded that these substances are only capable of inhibiting the function of the pituitary and of preventing pregnancy because of their oestrogenic activity.