Early postnatal alcohol exposure in rats: maternal behavior and estradiol levels.

Long Evans male and female rats were exposed to alcohol or control conditions during the early postnatal period, and their maternal behavior was assessed between 25 and 29 days of age. Maternal behavior was induced by exposing experimental animals to pups, and behaviors included retrieval of pups and proximity to pups. After 5 days of continuous exposure to pups, experimental animals were decapitated, and trunk blood was measured for levels of estradiol and progesterone. Alcohol-exposed animals showed a deficit in maternal behavior as measured by a longer latency to retrieve pups than rats that were not treated with alcohol. In addition, alcohol-exposed animals had lower levels of circulating estradiol than controls. These effects may also be explained by undernutrition as a result of artificial rearing. No difference in progesterone levels was found. As estradiol is important for the onset of maternal behavior in adult rats, it may be that the alcohol-induced decrease in estradiol levels underlies the deficit in maternal behavior exhibited by alcohol-exposed rats.