Maternal regulation of adrenocortical activity in the infant rat: Effects of feeding

Abstract

Basal and stress-induced corticosterone release in the infant rat has been shown to be inhibited by some aspect of maternal care. The following studies examined specific maternal cues that might be responsible for this regulation. In Experiments 1 and 2, 12-day-old pups remained with their dam but were either prevented or not from feeding; at the end of 24 hr, basal and stress-induced corticosterone levels were measured. Only those animals that were able to feed showed the hyporesponsiveness characteristic of nondeprived animals, suggesting that feeding rather than some other aspect of maternal care was the critical variable. In Experiment 3, all animals were maternally deprived, and some of them were fed via an intracheek cannula. Once again, feeding led to a pronounced diminution in both basal and stress-induced levels of corticosterone. Our results point to feeding as one of the critical features responsible for the inhibitory effect of the dam on the infant's adrenocortical activity.