Bumetanide Induced Increase of Renal Blood Flow in Conscious Dogs and its Relation to Local Renal Hormones (PGE, Kallikrein and Renin)

Abstract

Abstract Bumetanide (0.25 mg/kg intravenously) increases renal blood flow (RBF) for 40–60 min. in conscious dogs with chronically implanted flow probes. The time of maximum increase in RBF (10–15 min. after administration) proceeds maximum diuresis (20–30 min. after administration). A several fold increase in urinary PGE‐output occurs during the first 20 min. after bumetanide administration. Urinary PGE excretion is not increased during the later course of the increase in RBF. Urinary kallikrein excretion increases and this is highly correlated with the diuretic volume. Plasma renin activity (PRA) increases initially concomitantly with the increase in renal blood flow. Indomethacin treatment (5 mg/kg orally) lowers RBF and urinary PGE excretion. Bumetanide in indomethacin pretreated dogs does not modify RBF or urinary PGE output. The diuretic effect of bumetanide is reduced as is also the urinary kallikrein excretion, while the initial increase of PRA is absent. The results support the conclusion that the increase of RBF and PRA after bumetanide administration is dependent on an increased prostaglandin/kinin activity.