title: [Na+-ATPase in the gills of bass (Dicentrarchus labrax)].
abstract: The authors evidence a Mg2+ dependent ATPase activity stimulated by Na+ in absence of K+ in bass gill microsomes. As this stimulated ATPase shows different features from "baseline" activity measured in the absence of both Na+ and K+ ions (Mg2+-ATPase) and from 1mM ouabain sensitive (Na+ + K+)-ATPase, it has been ascribed to a distinct Na+-ATPase. In the present paper the optimal conditions for bass gill Na+-ATPase assay and the temperature dependence of the enzyme are reported. Moreover the Na+-ATPase appears to be insensitive to 1mM ouabain and 100% inhibited by 2,5mM ethacrynic acid. It is suggested a parallel diffusion of Na+- and (Na+ + K+)-ATPase and a possible physiological role of Na+ATPase in osmoregulation.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase; D027682:Cation Transport Proteins; D004976:Ethacrynic Acid / Q000494:pharmacology; D005399:Fishes / Q000378:metabolism*; D005880:Gills / Q000201:enzymology*; D008861:Microsomes / Q000201:enzymology; D010042:Ouabain / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D013696:Temperature
chemical_list: D027682:Cation Transport Proteins; D010042:Ouabain; D012964:Sodium; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; C021838:sodium-translocating ATPase; D004976:Ethacrynic Acid
vernacular_title: Na+-ATPasi in branchie di spigola (Dicentrarchus labrax).