Abstract
The purpose of this study was to examine the effect of high and low humidity at both high and low temperatures on pituitary-adrenal function in swine as measured by plasma adrenal corticoids, ACTH, GH, glucose and FFA. Corticoids and GH were significantly increased in response to low temperature, low humidity (4.4 C, 2.9 mm Hg vapor pressure) as compared to the control environment (21.1 C, 11.4 mm Hg) while ACTH, glucose and FFA were not affected. When humidity was increased (2.9 to 6.3 mm Hg) while temperature was held at 4.4 C, ACTH, glucose and FFA levels increased significantly. However, plasma corticoids and GH levels fell significantly in response to this treamtment. Plasma ACTH, GH, glucose and FFA were higher and corticoids lower at high temperature, low humidity (32.2 C, 10.5 mm Hg) as compared to these parameters at control conditions. Elevation of humidity (10.5 to 31.8 mm Hg) while at 32.2 C resulted in slight decreases in ACTH, GH, glucose and FFA and a slight increase in corticoids. Results suggest that stress may change the turnover rate of corticoids in the body and indicate that both plasma ACTH and corticoids should be determined to more accurately measure pituitary-adrenal responses to stress. Copyright © 1972. American Society of Animal Science. Copyright 1972 by American Society of Animal Science.