Effects of DDAVP on renal hemodynamics and renin secretion in subjects with essential hypertension

Intravenous (i.v.) infusion of the selective vasopressin (V2) agonist 1-desamino-8-D-arginine vasopressin (DDAVP, Desmopressin) in humans causes a fall in blood pressure, an increase in heart rate, and a rise in plasma renin and noradrenaline. The present study was designed to demonstrate the vasodilatory properties of DDAVP in the renal circulation and to describe the effect of DDAVP on renin secretion. Seven male subjects (31-63 years) with hypertension, who showed no signs of renal parenchymal disease, received an i.v. infusion of DDAVP (400 ng/kg in 10 minutes). They were studied at the time they were undergoing renal vein renin sampling and renal angiography as part of the diagnostic work-up of their hypertension. 131I-Hippurate clearance was used to measure effective renal plasma flow (ERPF). True renal plasma flow was calculated as ERPF divided by the renal extraction ratio of 131I-hippurate. 125I-Thalamate clearance was used to measure glomerular filtration rate (GFR). Measurements were made before and 15-20 minutes after administration of DDAVP. Angiography was performed in the same session after the last blood samples had been collected. In all patients the renal arteries were normal and the extraction ratios of 131I-hippurate and 125I-thalamate (Ehip, Ethal) were not different for the left and right kidney, and in all seven patients a diagnosis of essential hypertension was made. After DDAVP systolic blood pressure decreased by 14.4 mmHg (2.0-26.8) (mean, 95% confidence interval, p < 0.05). Diastolic blood pressure decreased by 12.1 mmHg (2.9-21.7, p < 0.01). Heart rate increased by 17.5 bpm (11.7-23.2, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)