K depletion modifies the properties of Sch-28080-sensitive K-ATPase in rat collecting duct

摘要: Two distinct Sch-28080-sensitive K-adenosine triphosphatases (K-ATPases) were previously described in the rat nephron: a ouabain-resistant K-ATPase (type I) present collecting ducts (CD) and ouabain-sensitive from II) located proximal tubules (PT) thick ascending limbs (TAL). In K-depleted rats, activity is increased CD, whereas it reduced PT TAL. Because expression of colonic H-K-ATPase restricted to CD we hypothesized that rats might be different types I II. Indeed, type III displays higher sensitivities ouabain Sch-28080 than II, lower sensitivity I, and, conversely can stimulated by Na+. Pharmacological differences between II K-ATPases confirmed [3H]ouabain binding experiments. Thus kidney expresses three differ their pharmacological kinetic properties, distribution profile along nephron behavior during K depletion.