Abstract
.Experiments are presented to show that a number of stressing agents produced their deleterious effects on the adrenals of the host by causing excessive adrenocorticotrophin (ACTH) production. Adrenocortical haemorrhages, that were evident when metopirone, adrenaline, or endotoxin was infused into normal sheep, were not seen following similar infusions into ACTH-maintained hypophysectomized sheep. Infusion of 50 i.u. ACTH over 11 hr, however, caused adrenocortical haemorrhages in both normal and hypophysectomized sheep. These results support the suggestion that excessive ACTH production causes the changes seen in the adrenals of sheep that succumb to cold exposure.