THE BROWN-NORWAY RAT DISPLAYS ENHANCED STRESS-INDUCED ACTH REACTIVITYAT DAY 18 AFTER 24-H MATERNAL-DEPRIVATION AT DAY 3

The effect of a 24-h maternal deprivation at day 3 was studied on the hypothalamus-pituitary-adrenal axis of 18-day-old Brown Norway pups, w hose stress-hyporesponsive period is similar to other rat strains. Dep rivation resulted at day 18 in reduced basal ACTH levels. The rate of onset and the duration of stress-induced ACTH release were enhanced. C RH mRNA, brain corticosteroid mRNA levels and corticosterone receptor levels were not affected by deprivation, but adrenal weight was increa sed. It is concluded that maternal deprivation has persistently dimini shed adrenocortical function in containment of the ACTH response to st ress. (C) 1997 Elsevier Science B.V.