Ethanol-induced alterations in the morphology and function of the rat ovary

The purpose of this study was to compare the effects of different dosages of ethanol on ovarian morphology and function. Holtzman rats, 20 days old, were divided into groups as follows: The rats in Group I were autopsied at 20 days of age, and those in Group II were placed on ad libitum chow and water diet; the rats in Groups III and V were fed on a liquid diet containing 2.5% or 5% ethanol respectively; Groups IV and VI were pair-fed controls to Groups III and V, respectively. Rats in Groups II, III, IV, and VI were maintained on the diets for 50-55 days and killed at late proestrus-estrus, while the animals in Group V did not exhibit estrous cycles and were killed on day 55 of treatment. The average increase in body weights of rats in Groups II, III, and IV was significantly greater than the increase in body weights of rats given 5% ethanol or their pair-fed controls. In the rats treated with 5% ethanol, vaginal opening was significantly delayed from the controls, estrous cycles were absent, ovarian weights were similar to those of the 20-day-old rats, ovaries contained corpora lutea of only one estrus, uteri weighted less than controls, and histologically, the uteri and vaginae were similar to those of 20-day-old rats. However, in the rats treated with 2.5% ethanol, all of the parameters were similar to those of the controls. The average serum alcohol level for the rats on the 5% ethanol diet was 249 mg%; the serum alcohol levels were at the lower limit of detection for the rats on the 2.5% ethanol diet. The data show that ovarian function was suppressed in the rats that received the 5% ethanol but not in rats on the 2.5% ethanol diet.