Myocardial Na, K-ATPase in one-kidney, one-clip hypertensive rats.
Myocardial ventricular Na, K-ATPase activity of normotensive rats was compared with that of healthy rats with chronic benign one-kidney, one-clip hypertension. The yield of protein (mg/g wet wt left plus right ventricles) in microsomal and sarcolemmal membrane fractions was the same for both normotensive and hypertensive rat ventricles. However, the yield of protein (mg/ventricle) was 26% greater in the hypertensive relative to the normotensive animals, consistent with the presence of hypertrophy, as also indicated by an increase in the ratio of ventricular to body weight and a shift in the isomyosin composition. Na, K-ATPase activity, sodium-dependent phosphorylation and ouabain binding were significantly (P less than 0.05) decreased (by 20%, 40%, and 45%, respectively) in the hypertensive rat ventricles when the data were expressed in units/g tissue wet weight. However, when expressed in units per ventricle, values in normotensive and hypertensive animals were similar. The molecular activity or turnover number of ventricular (and also renal) Na, K-ATPase activity was the same in both groups of animals. These results suggest that the decrease in myocardial specific Na, K-ATPase activity in the rat made hypertensive by removing one kidney and constricting the renal artery of the other kidney is related to the presence of cardiac hypertrophy.
D000818:Animals; D006332:Cardiomegaly / Q000201:enzymology; D006977:Hypertension, Renal / Q000201:enzymology*; D007668:Kidney / Q000201:enzymology / Q000648:ultrastructure; D008297:Male; D008861:Microsomes / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology*; D010042:Ouabain / Q000378:metabolism; D010766:Phosphorylation; D051381:Rats; D011919:Rats, Inbred Strains; D012508:Sarcolemma / Q000201:enzymology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase