Myocardial Na, K-ATPase in one-kidney, one-clip hypertensive rats

• Published in: Journal of molecular and cellular cardiology Vol. 18; no. 10; pp. 1085 - 1095
• Main Authors: Whitmer, K.R., Lee, J.H., Martin, A.F., Lane, L.K., Lee, S.W., Schwartz, A., Overbeck, H.W., Wallick, E.T.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.1986
• Subjects: adenosinetriphosphatase; Animals; Cardiomegaly - enzymology; Hypertension; Hypertension, Renal - enzymology; Hypertrophy; K-ATPase; Kidney - enzymology; Kidney - ultrastructure; Male; Microsomes - enzymology; myocardium; Myocardium - enzymology; Ouabain - metabolism; Phosphorylation; Rats; Rats, Inbred Strains; Sarcolemma - enzymology; Sodium pump; Sodium-Potassium-Exchanging ATPase - metabolism; Hypertension; K-ATPase; Sodium pump; Na; Hypertrophy
• DOI: 10.1016/S0022-2828(86)80295-4
• ISSN: 0022-2828

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<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.