Modification of corticosterone and glucose responses by sympatholytic agents in young chickens during acute heat exposure.
In four experiments, immature Athens Randombred (ARB) chickens were maintained at a moderate temperature, (24 degrees C., 45% R.H.). In Exps. 1 and 2 reserpine was given intramuscularly (0.75 mg./kg.) 12 hours before the heating episode was begun; in Exp. 3, propranolol was given intravenously (4 mg./kg.) 2 hours before heating; and in Exp. 4, dihydroergotamine was given intramuscularly (4 mg./kg.) 6 hours before heating. Rserpine and propranolol elevated plasma corticosterone before the heating episode began, but dihydorergotamine did not. Reserpine also raised plasma glucose levels before heating, but propranolol and dihdroergotamine did not. During the heating episodes, plasma glucose and plasma corticosterone increased in non-drug-treated birds; the increases were then followed by significant declines. In birds treated with reserpine, propranolol, and dihydroergotamine, however, elevated plasma corticosterone was maintained throughout the period of heating. Propranolol and dihydroergotamine also stabilized plasma glucose at higher levels during heating, but reserpine permitted the late period decline similar to that of non-drug-treated birds. These results indicate an adrenal cortical insufficiency during heat stroke and death in young chickens.
D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D002645:Chickens / Q000502:physiology*; D003345:Corticosterone / Q000097:blood*; D004088:Dihydroergotoxine / Q000494:pharmacology; D006358:Hot Temperature; D011433:Propranolol / Q000494:pharmacology; D012110:Reserpine / Q000494:pharmacology; D013312:Stress, Physiological / Q000662:veterinary; D013565:Sympatholytics / Q000494:pharmacology*; D013696:Temperature
D001786:Blood Glucose; D013565:Sympatholytics; D004088:Dihydroergotoxine; D012110:Reserpine; D011433:Propranolol; D003345:Corticosterone