Prostacyclin increases distal tubule HCO3 secretion in the rat.
We examined whether prostacyclin (PGI2), a prostaglandin synthesized in the renal cortex that increases adenosine 3',5'-cyclic monophosphate levels in distal nephron epithelia, mediates increased HCO3 secretion in in vivo perfused distal tubules of anesthetized rats given dietary HCO3. Animals eating a minimum electrolyte diet given 80 mM NaHCO3 drinking solution increased urine excretion of 6-keto-PGF1 alpha, a PGI2 metabolite, by 2.6 +/- 0.3-fold compared with those drinking distilled H2O. NaHCO3 animals infused with indomethacin to inhibit PGI2 synthesis had lower HCO3 secretion than those without indomethacin (-8.9 +/- 0.9 vs. -18.7 +/- 1.8 pmol.mm-1.min-1, P < 0.01). By contrast, NaHCO3 animals infused with both PGI2 and indomethacin had higher HCO3 secretion than those given indomethacin alone (-16.0 +/- 1.5, P < 0.02 vs. indomethacin group). HCO3 secretion was not different between controls with and without indomethacin but was higher in the PGI2 + indomethacin compared with the indomethacin alone controls (-11.2 +/- 1.2 vs. -4.5 +/- 0.5, P < 0.01). The data show that PGI2 increases distal tubule HCO3 secretion in rats and suggest that this agent contributes to the increased distal tubule HCO3 secretion induced by dietary HCO3.
Wesson
D E
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Texas Tech University Health Sciences Center, Lubbock 79430, USA.
D000818:Animals; D001639:Bicarbonates / Q000378:metabolism*; D001835:Body Weight; D004032:Diet; D011464:Epoprostenol / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D007686:Kidney Tubules, Distal / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D011677:Punctures; D051381:Rats; D011919:Rats, Inbred Strains; D017693:Sodium Bicarbonate / Q000494:pharmacology; D014556:Urine / Q000737:chemistry
D001639:Bicarbonates; D017693:Sodium Bicarbonate; D011464:Epoprostenol