Indices of stress in rats: effects of sex, perinatal alcohol and artificial rearing.

Three groups of rats were normally reared by dams, artificially reared but not exposed to alcohol or artificially reared and exposed to 6.6 g/kg/day of ethanol condensed into 8 h of each 24-h period. Alcohol exposure was given from postnatal day 4 through 9 and artificial rearing was conducted from postnatal day 4 to 12. In adulthood, approximately half of the rats were fitted with a chronic jugular catheter and were exposed to swim stress for 1 min in 21 degrees C water. Alcohol exposure augmented the corticosteroid stress response to the swim stress in female rats but not in male rats. The other half of the animals were tested for acquisition and extinction of a conditioned emotional response (CER). While alcohol exposure had no effects on the CER, extinction of CER was greatly accelerated by artificial rearing alone in female rats but not in male rats. Taken together, these findings suggest that some aspects of the stress response in female rats are more vulnerable to insults during the early postnatal period than those in male rats and that the insult-induced alterations can affect hormonal and behavioral measures differentially.