Role of prostaglandins in mediating the renal effects of atrial natriuretic factor

The natriuretic response to the intrarenal administration of atrial natriuretic factor (ANF) is accompanied by an increase in the synthesis of prostaglandins and by a redistribution of renal blood flow from the superficial to the deep cortex. This study was undertaken to define whether prostaglandins mediate the ANF-induced redistribution of renal blood flow and if prostaglandins and renal blood flow redistribution contribute to the natriuretic actions of ANF. In anesthetized dogs, the intrarenal administration of indomethacin (10 micrograms/kg/min) or the intravenous administration of meclofenamate (5 mg/kg) completely prevented the sixfold and twofold increments in urinary prostaglandin E2 and 6-keto-prostaglandin F1 alpha excretion, respectively; it also abolished the redistribution of renal blood flow to the deep cortex. However, ANF induced a similar natriuresis before (from 53 +/- 17 to 281 +/- 48 microEq/min) and after (from 45 +/- 13 to 273 +/- 60 microEq/min) the administration of prostaglandin synthesis inhibitors. It is concluded that the ANF-induced redistribution of renal blood flow to the deep cortex is prostaglandin-mediated but that neither redistribution nor increased prostaglandin synthesis is an important mediator of ANF's natriuretic action.