ACUTE AND CHRONIC INFLUENCE OF DIAZOXIDE ON ADRENAL-REGENERATION HYPERTENSION

Abstract
The antihypertensive activity of diazoxide was evaluated in rats with regenerating adrenal glands. The drug was given chronically in the drinking fluid, and also by subcutaneous injection at two intervals during the experiment. For a brief period diazoxide in the drinking fluid was replaced by hydrochlorothiazide. Diazoxide caused detectable sodium retention, despite which it reduced the intensity of hypertension and reduced the incidence, severity, and extent of the accompanying vascular lesions. The substitution of hydrochlorothiazide for diazoxide, or the subcutaneous administration of diazoxide to rats that were then consuming it in the drinking fluid, usually further depressed the blood pressure. It may thus be concluded that maximal blood pressure lowering effects of diazoxide were not achieved by oral ingestion, and that while the drug does afford a significant degree of protection against adrenal-regeneration hypertension it is less effective in this respect than hydrochlorothiazide, possibly because diazoxide causes sodium retention whereas hydrochlorothiazide promotes saluresis.