Abstract
ACTH releasing activities of epinephrine, acetylcholine, Pitressin, synthetic lysine vasopressin and Pitocin injected into the carotid artery of rat were studied.
Pitressin and synthetic lysine vasopressin possessed the strongest potencies.
The dose threshold of Pitressin to induce an appreciable ACTH release fell between 40 and 80mU per rat.
Pitressin incubated with a kidney homogenate lost its ACTH releasing activity.
The rise in blood ACTH level following an intracarotid injection of 5ug. epinephrine was not altered when 40mU of Pitressin was administered simultaneously.
The authors are indebted to Prof. VINCENT DUVIGNEALD for the synthetic lysine vasopressin employed in this experiment. This study was supported by U. S. P. H. S. grant A-256.
