title: Bath and lumen effects of SITS on PAH transport by isolated perfused renal tubules.
abstract: Effects of 4-acetamido-4'-isothiocyano-2,2'-disulfonic stilbene (SITS) in bath or lumen on p-aminohippurate (PAH) transport by isolated perfused snake (Thamnophis spp.) distal-proximal renal tubules were studied. Addition of SITS to the bath in concentrations as low as 10(-10) M irreversibly depressed net PAH secretion. Addition of 10(-4) M SITS in the bath depressed net PAH secretion by about 60% without affecting apparent permeability of luminal membrane to PAH (PL) or net fluid absorption. Cellular PAH concentration was reduced by about 70% at this time but was still greater than that in the bath. Apparent permeability of peritubular membrane, determined from PAH efflux from tubules with oil-filled lumens, was unchanged even with 10(-3) M SITS in bath. These data indicate that SITS in the bath inhibits PAH transport from bath into cells without enhancing passive efflux from cells to bath. Addition of 10(-4) M SITS to the lumen alone depressed net PAH secretion and PL by about 60%, but this depression was reversed when SITS was removed from the lumen. These data suggest that PAH moves from cells to lumen by a mediated process distinctly different from that fro transport into cells from bath.
mesh_terms: D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000494:pharmacology*; D000618:Aminohippuric Acids / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D003864:Depression, Chemical; D066298:In Vitro Techniques; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D008433:Mathematics; D012911:Snakes / Q000378:metabolism*; D013267:Stilbenes / Q000494:pharmacology*; D010130:p-Aminohippuric Acid / Q000378:metabolism*
chemical_list: D000618:Aminohippuric Acids; D013267:Stilbenes; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D010130:p-Aminohippuric Acid