title: ATP-stimulated tetraethylammonium transport by rabbit renal brush border membrane vesicles.
abstract: These studies examined the ability of ATP to stimulate transport of the organic cation tetraethylammonium (TEA) into proximal tubular brush border membrane vesicles. ATP markedly enhanced TEA uptake for 1 h or more to values severalfold above those observed in the absence of ATP. The poorly hydrolyzable analogue of ATP, AMP-PNP (adenyl-5'-yl imidodiphosphate), reduced the effect of ATP but alone did not stimulate TEA uptake. GTP and ITP also stimulated TEA uptake, whereas other nucleotides did not. ATP-stimulated TEA uptake was saturable, temperature-dependent, and markedly reduced by the organic cations amiloride, quinidine, cimetidine, and verapamil, but only modestly reduced by the organic cations N'-methylnicotinamide and choline. Some inhibitors of other transport ATPases, including N-ethylmaleimide, N,N'-dicyclohexylcarbodiimide, and oligomycin, reduced the effect of ATP, whereas ouabain, vanadate, and azide did not. 4,4'-Diisothiocyanatostilbene-2,2'-disulfonic acid also reduced TEA uptake in the presence of ATP. Vinblastine, but not actinomycin D and colchicine (all inhibitors of P-glycoprotein-mediated transport), reduced TEA uptake. The reduction of TEA transport by amiloride and cimetidine was most consistent with competitive inhibition, whereas the inhibition produced by N-ethylmaleimide and vinblastine evidently was not. ATP also stimulated uptake of N'-methylnicotinamide but not that of vinblastine. These studies have identified a previously unrecognized process by which ATP hydrolysis may directly energize the reabsorption of organic cations from the renal tubule lumen.
authors: Department of Medicine, Veterans Affairs Medical Center, Indiana University Medical Center, Indianapolis 46202-5116.
authors: T D
authors: TD
authors: McKinney
authors: M A
authors: MA
authors: Hosford
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D002021:Buffers; D007672:Kidney Cortex / Q000378:metabolism* / Q000648:ultrastructure; D007700:Kinetics; D008297:Male; D008871:Microvilli / Q000378:metabolism; D011817:Rabbits; D013696:Temperature; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000378:metabolism*; D014638:Vanadates / Q000494:pharmacology
chemical_list: D002021:Buffers; D013757:Tetraethylammonium Compounds; D014638:Vanadates; D019789:Tetraethylammonium; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases