Changes in rat ventricular isomyosins with regression of cardiac hypertrophy

The changes in ventricular isomyosin composition and Ca2+-activated ATPase activity occurring with regression of both hypertension and cardiac hypertrophy were investigated by using polyacrylamide gel electrophoresis under nondenaturing conditions, heavy chain peptide mapping, and an enzymatic assay. Eight control male Wistar rats and 14 two-kidney, one clip (Goldblatt II) hypertensive rats were studied from the fifth week of age. At 10 weeks of age, five Goldblatt II rats and four normotensive controls were killed. Five other Goldblatt II rats underwent nephrectomy of the ischemic kidney, which resulted in subsequent normalization of blood pressure. The remaining four control, four Goldblatt II rats, and five nephrectomized rats were killed at 15 weeks of age. Both the 10- and 15-week-old hypertensive rats had a significantly higher (p<0.001) biventricular weight to body weight ratio than the age-matched controls (3.84 ± 0.76 x 10-2 vs 2.75 ± 0.25 x 10-2; 5.93 ± 2.26 x 10-2 vs 2.65 ± ...