Inhibition of a Cl-/HCO3(-)ATPase in the avian salt gland by furosemide and ethacrynic acid.
An ouabain-insensitive, Mg2+-dependent, chloride- and bicarbonate-stimulated ATPase is present in salt gland homogenates of domestic ducks (Anas platyrhynchos). Furosemide and ethacrynic acid are non-competitive inhibitors of this enzyme in vitro. The inhibitor constant of furosemide is Ki = 2.5 mM and of ethacrynic acid Ki = 1.9 mM. In contrast, under the same conditions the salt gland Na+/K+-ATPase activity is not inhibited by furosemide, whereas ethacrynic acid becomes inhibitory only at higher concentrations (10 mM).
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors*; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D017301:Ca(2+) Mg(2+)-ATPase; D002712:Chlorides / Q000494:pharmacology; D004372:Ducks; D004976:Ethacrynic Acid / Q000494:pharmacology*; D005665:Furosemide / Q000494:pharmacology*; D012491:Salt Gland / Q000201:enzymology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors
D001639:Bicarbonates; D002712:Chlorides; D005665:Furosemide; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; D000254:Sodium-Potassium-Exchanging ATPase; D004976:Ethacrynic Acid