ENDOCRINE FACTORS IN THE RESPONSE OF THE HYPOTHYROID RAT TO COLD

Abstract
The hypothyroid rat subjected to low environmental temperature exhibits a greater than normal adrenal response as measured by depletion of adrenal ascorbic acid and ester cholesterol. Survival time in cold is not prolonged by the administration of ACTH or cortical extract; only thyroxine provides normal resistance. Adrenal hypertrophy and thymic involution following continuous exposure to low temperature are as great in the hypothyroid as in the normal rat, despite which the former fails to survive.