Experimental hypertension in pregnant sheep

¹ Department of Physiology, School of Veterinary Medicine, University of California, Davis; Department of Medicine, University of Southern California, Los Angeles, California; Departments of Obstetrics and Gynecology, State University of New York Downstate Medical Center, Brooklyn, New York; and University of California at Los Angeles, California

Sheep with spontaneously occurring or experimentally induced toxemia of pregnancy do not develop hypertension despite the presence of a marked renal ischemia. The present study was undertaken in order to investigate whether pregnant sheep, like pregnant dogs and rats, do not exhibit hypertension when subjected to renal artery constriction. Bilateral constriction of the renal arteries was performed on pregnant ewes by a modified Goldblatt-Wakerlin technique, after control blood pressure had been recorded for several days. Blood pressure and BUN were measured throughout pregnancy and following delivery. All the animals which had renal artery constriction developed severe hypertension with retinal changes similar to those of human hypertension. The pregnancy did not affect the course of the hypertension nor did the hypertension alter the course of pregnancy.