HEMODYNAMIC CHANGES FOLLOWING AORTIC CONSTRICTION IN NORMAL AND IN HYPOPHYSECTOMIZED RATS

Abstract

Systolic and diastolic blood pressures were measured electrically, during ether anesthesia, in the carotid and femoral arteries at different times after subdiaphragmatic aortic constriction in normal and hypophysectomized rats. In normal rats there is a rise in both systolic and diastolic pressures above the stricture, followed by a transitory drop, then a gradual increase to hypertensive levels. Below the constriction the pressure falls sharply with a great reduction in pulse pressure, but rises to values above normal in a few days. In hypophysectomized rats the initial changes parallel those in normal rats, but the rise of the blood pressure to hypertensive levels both above and below the stricture is absent. Left ventricular hypertrophy develops from about the second day on in normal but not in hypophysectomized rats. After constriction there is a small decrease in heart rate followed by a pronounced tachycardia in normal but not in hypophysectomized rats. There is some indication of an increased subdiaphragmatic peripheral resistance in hypophysectomized rats.