Nature of Na+-independent stimulation of renal transport of p-aminohippurate by exogenous metabolites.
The relationship between p-aminohippurate (PAH) and Na+ transport in rabbit kidney cortical slices was examined under optimal metabolic conditions. Addition of lactate, pyruvate and acetate to the incubation medium stimulated PAH transport and accumulation, but had no effect on active Na+ efflux from the slices. Conversely, small concentration of F-, in the presence of acetate, decreased PAH transport and accumulation, but had no effect on Na+ efflux. These observations constitute evidence that, in addition to Na+ cotransport [M. I. Sheikh and J. V. Møller Biochem. J. 208, 243 (1982)], PAH uptake is metabolically stimulated by a Na+-independent pathway. This could occur either by a direct metabolic effect on the PAH carrier, or by exchange with intracellular anions that are generated in the presence of exogenous substrate. In support of the latter possibility the PAH carrier is demonstrated to function as an anion exchanger of PAH and fumurate after preloading of the slices with fumurate under anaerobic conditions.
D000085:Acetates / Q000494:pharmacology; D000332:Aerobiosis; D000618:Aminohippuric Acids / Q000378:metabolism*; D000693:Anaerobiosis; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D005260:Female; D066298:In Vitro Techniques; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D007773:Lactates / Q000494:pharmacology; D019344:Lactic Acid; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D011773:Pyruvates / Q000494:pharmacology; D019289:Pyruvic Acid; D011817:Rabbits; D012964:Sodium / Q000378:metabolism*; D012969:Sodium Fluoride / Q000494:pharmacology; D010130:p-Aminohippuric Acid / Q000378:metabolism*
D000085:Acetates; D000618:Aminohippuric Acids; D007773:Lactates; D011773:Pyruvates; D019344:Lactic Acid; D010042:Ouabain; D019289:Pyruvic Acid; D012969:Sodium Fluoride; D012964:Sodium; D010130:p-Aminohippuric Acid