The effect of PGI2 on canine renal function and hemodynamics

The effect of prostaglandin I₂ (prostacyclin) on renal and intrarenal hemodynamics and function was studied in mongrel dogs to elucidate the role of this novel prostaglandin in renal physiology. Starting at a dose of 10^?8 g/kg/min, PGI₂ decreased renal vascular resistance and redistributed the blood flow away from the outer cortex (zone 1) and towards the juxtamedullary cortex (zone 4). At 3 × 10^?8 g/kg/min, the renal vascular resistance decreased even further, but at this dose the mean arterial blood pressure also declined 13% indicating recirculation of this prostaglandin. PGI₂ infusion at a vasodilatory dose resulted in natriuresis and kaliuresis. With a decline in filtration fraction, these changes were most likely secondary to the hemodynamic effects of this prostaglandin. Unlike PGE₂, PGI₂ had no direct effect on free water clearance indicating lack of activity at the collecting duct. PGI₂ may be the important renal prostaglandin involved in modulating renal vascular resistance and intrarenal hemodynamics as well as influencing systemic blood pressure.