[Effect of ethanol in the pre-ovulatory period on the ovarian cycle, progesterone and estradiol in the rat].

The effect of high doses of ethanol (2 and 4 g/kg) administered to rats in pre-ovulatory periods (18th hour of diestrus) was studied. Plasma levels of estradiol and progesterone were measured at 10 hours of oestrus and changes in the ovarian cycle and the number of mature follicles were recorded. Compared with the control group, the receptive phase of estrus of the treated animals was longer lasting over 2 to 3 days. There was also an increase in the number of mature follicles as well as an increase in the plasma level of estradiol on the morning of estrus. Progesterone values showed no significant variations. Ethanol administered at the 18th hour of diestrus inhibits ovulation but not follicle development and allows the maintenance of high levels of estrogens on the morning of estrus. As a result the keratinization of the vaginal epithelium and the estrus phase are prolonged by 2 or 3 days.