Glomerulotubular balance and prostaglandin synthesis.
We have tested a hypothesis proposed to explain glomerulotubular balance (GTB) as a consequence of variations in prostaglandin synthesis. Arachidonic acid (40 micrograms x kg-1 x min-1) infused into the renal artery of anesthetized dogs raised renal blood flow (RBF) by 41 +/- 5% in hydropenic and by 24 +/- 11% in volume-expanded dogs, but the absolute changes were similar. The infusion of arachidonic acid after the administration of indomethacin (10 mg x kg-1) had no effect on RBF. Arachidonic acid infusion increased the excretion of sodium and chloride in hydropenic dogs but not after the administration of ethacrynic acid in volume-expanded dogs. During continued infusion of ethacrynic acid, the glomerular filtration rate (GFR) was lowered by suprarenal aortic constriction and raised by carotid constriction. A linear relationship between electrolyte reabsorption and GFR (GTB) was observed when GFR was varied between 20 and 110% of control. GTB and tubular reabsorption at comparable GFR were not significantly altered during arachidonic acid infusion or after indomethacin administration. In all experimental settings, bicarbonate, chloride, and sodium reabsorption were altered in molar ratios of 1:2:3 during variations in GFR. We conclude that GTB is independent of variations in prostaglandin synthesis.
D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D004285:Dogs; D004976:Ethacrynic Acid / Q000494:pharmacology; D005260:Female; D005919:Glomerular Filtration Rate; D006863:Hydrogen-Ion Concentration; D007213:Indomethacin / Q000494:pharmacology; D007678:Kidney Glomerulus / Q000502:physiology*; D007687:Kidney Tubules, Proximal / Q000502:physiology*; D008297:Male; D009318:Natriuresis; D011453:Prostaglandins / Q000096:biosynthesis*; D012079:Renal Circulation / Q000187:drug effects; D014882:Water-Electrolyte Balance
D001095:Arachidonic Acids; D011453:Prostaglandins; D016718:Arachidonic Acid; D004976:Ethacrynic Acid; D007213:Indomethacin