Stressor Effect of Hypothermia in the Rat

¹ From the Departments of Pathology and Surgery, Section of Experimental Surgery, University of Pittsburgh School of Medicine, and Veterans Administration Hospital, Pittsburgh, Pennsylvania

The effect of hypothermia upon the adrenal cortex of the rat was evaluated by comparing the weights, histochemical and morphological appearance and ascorbic acid content of adrenals from cooled animals under ether and Nembutal anesthesia with normothermic controls. Hypothermia with ether narcosis for 2 hours resulted in a statistically significant decrease in adrenal weight related to loss of water and solids. Histologically, a decrease of adrenal cortical sudanophilia and cholesterol and/or esters was noted in approximately one-half of these animals and the ascorbic acid content of these glands was significantly decreased. The adrenals of rats subjected to hypothermia with ether for 6 hours however, were similar to those of normothermic controls. Similarly, short and long term hypothermia with Nembutal anesthesia failed to reveal any alteration in the adrenal cortex. These findings have been interpreted as indicating that in the rat an initial stress is attendant with hypothermia when ether anesthesia is employed.