Reversibility of endocrine changes produced in guinea pigs by exposure to cold

¹ Veterans Administration Hospital, Sepulveda, California

Guinea pigs were exposed continuously to a temperature of 2–4 C for 6 months. They were then reacclimatized to room temperature, and after 4–6 months certain tests were carried out. During control collections and following exposure to cold the previously cold-exposed animals exhibited urinary corticoid excretion values which were approximately 10% below those of their controls. Following intraperitoneal injection of ACTH the response was approximately 20% greater. However, these differences were not statistically significant. Oral glucose tolerance tests revealed definite evidence of reduction in tolerance in the previously cold-exposed animals. Six animals exhibited 150-min values which exceeded by more than 20 mg/ 100 ml the highest value observed in the controls. Fourteen others whose values fell within this limit exhibited a statistically significant increase in the 150-min value as compared with the controls. The PBI values were the same in each group. There were no histological residues in the pituitary, adrenal, pancreas, and thyroid glands.

Key Words: glucose tolerance • thyroid • reacclimatization • adrenals

Submitted on July 30, 1964