Pressor effect of subcutaneous renin in dogs, and effect of reserpine, l-hydrazinophthalazine and hexamethonium on renin hypertension

¹ Departments of Medicine, Peter Bent Brigham Hospital and Harvard Medical School, Boston, Massachusetts

The pressor effect of series of subcutaneous injections of hog renin was studied in the dog, as well as the modification of the pressor effects of renin by reserpine, hydralazine (l-hydrazinophthalazine) and hexamethonium. In 22 of 27 experiments, short series of subcutaneous renin injections (1–37 days) in doses of 550–1800 cat units/day were repeatedly followed by moderate elevations of systolic and diastolic blood pressure, whereas control injections of saline, ACTH or extracts of liver were without effect on the blood pressure. In a number of instances, but not in all, a definite increase in plasma renin could be demonstrated during the pressor effect of renin. The pressor effect of subcutaneous renin was still observed during oral administration of reserpine (0.25 mg/day) and hexamethonium (250–500 mg/day) but was often absent during the administration of hydralazine (25 mg/day). The pressor response to intravenous renin was increased in animals receiving reserpine and hexamethonium and decreased after hydralazine. In vitro experiments with these three drugs failed to indicate any significant effect on the formation or destruction of hypertensin.