title: Stimulative effect of Ba2+ on p-aminohippurate transport in rat kidney cortical slices.
abstract: BaCl2 stimulated significantly p-aminohippurate (PAH) accumulation in rat kidney cortical slices. The accumulation, however, was not stimulated by Sr2+, Mn2+ and Mg2+. Pretreatment of the slices with Ba2+ also increased PAH accumulation in the slices during incubation without BaCl2. Kinetical analyses of PAH accumulation showed that the effect of Ba2+ was to increase Vmax. No evidence for the effect of Ba2+ on PAH efflux from the slices was obtained. Thus, evidence indicating that Ba2+ stimulated PAH influx to the kidney cell was presented. Water distribution and energy metabolism in the slices were not related to the stimulative effect of Ba2+ on PAH accumulation. Ba2+ slightly lowered Na+ concentration in the slices. However, in the presence of ouabain, further addition of Ba2+ recovered PAH accumulation to a control value in spite of poor Na+ gradient as compared with that in control slices. Therefore, it is suggested that stimulation of PAH accumulation by Ba2+ was not due to changes in Na+ gradient. No stimulation of tetraethylammonium (TEA), an organic base, transport system by Ba2+ was observed. These data suggest that Ba2+ specifically stimulates the organic acid transport system in rat kidney cortical slices by increasing PAH influx to the cells.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000618:Aminohippuric Acids / Q000378:metabolism*; D000818:Animals; D001464:Barium / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D001834:Body Water / Q000378:metabolism; D002412:Cations / Q000494:pharmacology; D005110:Extracellular Space / Q000378:metabolism; D066298:In Vitro Techniques; D007672:Kidney Cortex / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000378:metabolism; D010130:p-Aminohippuric Acid / Q000378:metabolism*
chemical_list: D000618:Aminohippuric Acids; D002412:Cations; D013757:Tetraethylammonium Compounds; D001464:Barium; D019789:Tetraethylammonium; D000255:Adenosine Triphosphate; D012964:Sodium; D010130:p-Aminohippuric Acid