title: The loop diuretic furosemide as non-competitive inhibitor of C1-/HCO3-ATPases of vertebrate kidneys and insect rectum.
abstract: 1. The effect of the diuretic drug furosemide was studied in detail on ouabain-insensitive, SCN- and OCN- -sensitive C1-/HCO-3-ATPase in homogenates from larval dragonfly rectum (Aeshna cyanea), frog (Rana temporaria) and mouse (Mus musculus) kidney. 2. The in vitro inhibition by the drug studied on the HCO-3-activated enzyme is non-competitive with an inhibitor constant of Ki=4.3 mM furosemide in the case of insect rectum and Ki=0.9 mM furosemide in the case of frog and mouse kidney. 3. Furosemide even at 10 mM concentration which completely inhibits the anion-dependent ATPase has only a little inhibitory effect on the Na+/K+-ATPase of the 3 tissues. 4. The data suggest that furosemide may affect an active chloride transport system involving a C1-/HCO-3-ATPase.
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors*; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D005665:Furosemide / Q000494:pharmacology*; D066298:In Vitro Techniques; D007313:Insecta / Q000201:enzymology*; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D008138:Loop of Henle / Q000378:metabolism; D051379:Mice; D011896:Rana temporaria; D012007:Rectum / Q000201:enzymology
chemical_list: D001639:Bicarbonates; D002712:Chlorides; D005665:Furosemide; D000251:Adenosine Triphosphatases