Thermoendocrine influences on maternal nesting behavior in rats.

Adrenalectomy-ovariectomy (adex-ovex) of mother rats resulted in prolonged nest bouts with their young. Glucocorticoid, but not progesterone or aldosterone, replacement therapy to adex-ovex dams limited the duration of maternal nesting bouts by successfully restoring the chronic vulnerability of these mother rats to the acute thermal consequences of huddling with the young. This vulnerability appeared to be due to a chronic elevation of maternal temperature. When the heat load of hormone-disrupted mothers was chronically elevated, the dams were subject to an acute rise in temperature while huddling with their young, and nest bouts were curtailed.