Effects of estradiol benzoate and MER-25 on ethanol consumption in the ovariectomized rat.

Daily injections of estradiol benzoate (EB) administered to ovariectomized rats given continuous access to a 10% ethanol solution, to water, and to laboratory chow led to decreases in ethanol consumption. The suppression was transient; ethanol consumption returned to the level of oil-treated control animals after 14 days despite continued hormone administration. This pattern of change in ethanol consumption closely resembled previously reported effects of EB on food intake. It is proposed that a common mechanism was responsible for EB-induced suppression of both food and ethanol intake. Ethamoxytriphetol, MER-25, which antagonizes many estrogen-dependent effects but which mimics the action of EB on food intake, also led to decreases in ethanol consumption that paralleled those reported for food intake. These behavioral effects of EB and MEr-25 were shown not to be due to altered ethanol metabolism or to result from malaise developing out of an interaction between EB and ethanol. It is thus suggested that voluntary consumption of ethanol by the rat is largely due to its caloric content. The relevance of these results for several recent reports of decreased ethanol intake during pregnancy is discussed.