Category Archives: Hypertrophy

Alterations of myosin isoenzymes and ADP/ATP carrier in Goldblatt hypertensive rats (part 10)

Using Western immunoblot analysis, the authors have repeatedly observed marked changes in AAC protein content in wild-type cells grown under different conditions. Low levels of AAC protein were detected in cells cultured in growth media with reduced oxygen concentrations. The relative levels of AAC transcripts in wild-type cells grown in different substrates resembled the content of AAC protein in whole cells, being markedly reduced under … Continue reading

Alterations of myosin isoenzymes and ADP/ATP carrier in Goldblatt hypertensive rats (part 9)

AAC plays a key role in the control of mitochondrial oxidative phosphorylation. In this study, the reduction in AAC may have interfered, in that AAC transport of ATP to the cytoplasm and counter-transport of ADP into the mitochondrial matrix across the membrane results in reduction of cytosolic ATP and increase in mitochondrial ATP concentrations in Goldblatt hypertensive rats. Interestingly, previous studies and the present study … Continue reading

Alterations of myosin isoenzymes and ADP/ATP carrier in Goldblatt hypertensive rats (part 8)

Hypertrophy in which the rate of myosin ATPase activity and the velocity of muscle shortening are decreased without necessarily concordant heart failure has been defined as ‘pathological’. In the present study, our pressure overload-compensated hypertrophy model, the Goldblatt rat, meets the requirements for classification as ‘pathological’ according to the above authors. We feel that the decreased ATPase and dT/dt max values are part of a … Continue reading

Alterations of myosin isoenzymes and ADP/ATP carrier in Goldblatt hypertensive rats (part 7)

DISCUSSION Based on previous studies, the myosins of rat ventricular myocardium have been separated by PGE into three isoenzymes, ie, V1, V2 and V3, whose electrophoretic mobility becomes slower and ATPase activity becomes lower in that order. Furthermore, under some physiological or pathological conditions, the rat ventricular myosin isoenzyme pattern changes in parallel with changes in myosin ATPase activity . Our results show that cardiac hypertrophy … Continue reading

Alterations of myosin isoenzymes and ADP/ATP carrier in Goldblatt hypertensive rats (part 6)

Figure 2 shows that the AAC content ratio (the ratio of AAC:total mitochondrial membrane proteins) in Goldblatt rats was significantly decreased, from 11.8±0.5 to 10.0±0.4 (% mitochondrial protein), compared with that of control rats (P<0.05). Figure 3 shows the results of PGE (3 a) and densitometry (3b) obtained from extracts of the left ventricular myosin isoenzyme in control and Gold-blatt rats. Figure 3a shows the … Continue reading

Alterations of myosin isoenzymes and ADP/ATP carrier in Goldblatt hypertensive rats (part 5)

RESULTS The values of SBP, PR and tissue weights are shown in Table 1. It can be seen that myocardial hypertrophy developed in the Goldblatt rats. That is, hearts and ventricles of Goldblatt rats were 2.1 and 2.2, respectively, times heavier than those of control rats. SBP and PR in Goldblatt rats were significantly higher than in control rats (P<0.01, P<0.05, respectively). Figure 1 shows the … Continue reading

Alterations of myosin isoenzymes and ADP/ATP carrier in Goldblatt hypertensive rats (part 4)

Mitochondrial membrane protein extraction and determination of AAC content: The left ventricles were minced, homogenized and centrifuged, and the mitochondrial membranes were separated according to the method of Tzagoloff et al . The minced left ventricular myocardium was homogenized in 50 mmol Tris-HCl buffer (pH 7.4) containing 250 mmol sucrose and 1 mmol EDTA with a glass homogen-izer at 4°C. All the following procedures were performed … Continue reading

Alterations of myosin isoenzymes and ADP/ATP carrier in Goldblatt hypertensive rats (part 3)

Tissues: Fourteen-week-old Goldblatt and control rats were laparotomized under diethylether anesthesia . Blood was collected from the abdominal vein, and the sera were used for biochemical analysis. Hearts were immediately removed and dissected into ventricles. Then they were weighed, frozen in liquid nitrogen and stored at -70°C until use. Myosin isoenzyme extraction and PGE: Native myosin was extracted from the left ventricles according to the method … Continue reading

Alterations of myosin isoenzymes and ADP/ATP carrier in Goldblatt hypertensive rats (part 2)

In the present study, to determine whether the AAC content ratio and myosin isoenzyme pattern are changed in cardiac hypertrophy, we measured AAC and determined myosin isoenzyme pattern by using SDS-PAGE, PGE and densitometry, and investigated their pathophysiological significance and relationship in myocardial energetics and metabolism in Goldblatt hypertensive rats. ANIMALS AND METHODS

Alterations of myosin isoenzymes and ADP/ATP carrier in Goldblatt hypertensive rats (part 1)

The ADP/ATP carrier (AAC or adenine nucleotide translocator), the most abundant protein in the inner mitochondrial membrane , mediates the exchange of ATP and ADP across the membrane . Numerous earlier studies have identified the AAC protein as the major site for adenine nucleotide exchange between the mitochondrial matrix and the cytoplasm, and a key point for regulation of adenine-nucleotide ratios and the energy charge of the … Continue reading