Enhanced renal prostaglandin production in the dog. The effect of sodium arachidonate in nonfiltering kidney.

Abstract

Sodium arachidonate, 10(-5) g/kg per minute, was infused into the renal artery of a nonfiltering canine kidney in situ in order to determine the effects of enhanced prostaglandin synthesis on renal blood flow and its distribution in circumstances where prostaglandins produced in the medulla could not gain access to the cortex via tubular fluid. The contralateral normal kidney was also infused with sodium arachidonate and served as control. Radioactive microspheres were used to calculate the hemodynamic effects. In the nonfiltering kidney, the total renal blood flow increased after sodium arachidonate from a mean of 105 ml/min per 100 g to 146 ml/min per 100 g (P less than 0.01). This increase was completely abolished by prior treatment with indomethacin, 8 mg/kg, intravenously. The normal kidney responded qualitatively the same as the nonfiltering side. In both kidneys, blood flow increased significantly to all cortical zones except the outermost (zone 1), but the fractional distribution of renal blood flow was significantly increased only in the innermost cortex (zone 4). Since the kidneys were nonfiltering, the increase of renal blood flow during infusion of arachidonic acid cannot be explained by prostaglandins being transported from renal medulla to the cortex through renal tubules. Most likely prostaglandins are produced locally in the cortex and have only local effects.