PROTECTION OF ADRENALECTOMIZED RATS AGAINST A HIGH TEMPERATURE

Abstract

Both normal and adrenalectomized rats, mostly S, weighing from 200 to 340 grams were exposed to a temp. of 38.7[degree]C. for 4 hrs. in an atmosphere of high humidity. 93% of the normal rats survived while only 14 to 17% of the untreated adrenalectomized rats survived. NaCl afforded some protection since 27 and 53% of the adrenalectomized rats given 1% NaCl to drink, survived. Treatment of adrenalectomized rats with desoxycortico-sterone acetate was nearly adequate since 78 and 89% survived. About the same survival was obtained with adrenal extract, namely, 89%. The normal or protected adrenalectomized rats were active and restless while the other rate became quiet and unresponsive. The body temp. peak was reached during the 3d hr. in the normal, DCA-treated adrenalectomized and extract-treated adrenalectomized ani-mals and in the 4th hr. in the others. The temp. rise was greatest in the normal, DCA-treated adrenalectomized and extract-treated adrenalectomized rats. Water content of brain, blood, muscle and skin was detd. with and without exposure to heat. The untreated and NaCl-treated adrenal-ectomized rats showed the greatest blood cone. There was a loss of water from the skin in all animals except the DCA- treated adrenalectomized rats, the greatest loss being in the normal animals. Salivation w,as more copious in the normal than in the unprotected adrenalectomized rats. Since DCA protects as well as adrenal extract and acts most like Na factor in its physiologic properties it may be the Na factor which is responsible for the protection afforded by adrenal extract.