Effects of prostaglandin E2, I2 and F2 alpha on systemic and renal hemodynamics, renal function and renin secretion in anesthetized dogs.

Abstract

Effects of intrarenal-arterial (i.r.a.) and intravenous (i.v.) infusions of PGE2, I2 and F2 alpha on systemic blood pressure (BP), heart rate (HR), renal blood flow (RBF), urine volume (UV), renal function and plasma renin activity (PRA) of the renal venous blood (RVPRA) were investigated. A dose-dependent fall in BP was observed with PGE2 and I2 and was accompanied by a tachycardia (PGE2 < I2, i.r.a. < i.v.). PGE2 and I2 induced increases in RBF and UV in a roughly dose-dependent manner (PGE2 > I2, i.r.a. > i.v.), however, antidiuresis was observed with the highest intravenously given dose of PGI2 (300 ng/kg/min) such being ascribed to a pronounced hypotension. Changes in electrolyte excretion induced by PGE2 and I2 were similar to the pattern of those in RBF or UV. Neither PGE2 or I2 produced any significant changes in the glomerular filtration rate (GFR). The diuretic effect of PGE2 and F2 alpha correlated with osmolar clearance (Cosm) (r = 0.89, p < 0.01; r = 0.55, p < 0.01) and free water clearance (CH2O) (r = 0.52, p < 0.01; r = 0.83, p < 0.01), whereas that of PGI2, only with Cosm (r = 0.74, p < 0.01). PGF2 alpha produced the weakest changes in the parameters described above. PGE2 and I2 (30 ng/kg/min, i.r.a.), but not PGF2 alpha, produced a significant elevation of RVPRA without any significant change in BP. These findings suggest that PGE2 plays a primary role in the kidney, whereas PGI2 is important in the regulation of the systemic circulation, and that PGE2, I2 and F2 alpha all have different modes of action in producing diuresis. Both PGE2 and I2 may participate in the control of renin secretion.