부산대학교 도서관

Protein kinase C (PKC) is a family of at least 11 isozymes and known to play a crucial role in myocardial growth. The present study was performed to investigate whether PKC-isozymes are differentially regulated during the development of volume-overload cardiac hypertrophy. After 2, 7 and 30 days of sham or aortocaval shunt operation in male Wistar rats, PKC-activity and the expression of cardiac PKC-isozymes (PKC-α, δ and ε) were determined at the protein and at the mRNA-level in the left and the right ventricle separately. Myocardial hypertrophy after 2, 7 and 30 days of aortocaval shunt was more pronounced in the right than in the left ventricle. Right ventricular hypertrophywas associated with an increased PKC-enzyme activity, a selectively enhanced protein expression of cytosolic PKC-δ (day 7:+83 ± 12%, day 30:+94 ± 14%) and PKC-α (day 7:+48 ± 11%, day 30:+62 ± 16%) and a transcriptional upregulation of the absolute mRNA-levels of these PKC-isozymes in the aortocaval shunt group as compared to controls. In contrast, the expression of PKC-ε was unchanged. A significant upregulation of PKC-δ both on the protein and on the mRNA-level was also noted in volume-overload induced left ventricular hypertrophy, whereas the expression of PKC-α and PKC-ε were not altered. Furthermore, the expression of calcineurin in both ventricles was not significantly changed in response to volume-overload. This study characterizes in the left and right ventricle a differential regulation of the dominant PKC-isozymes in volume-overload cardiac hypertrophy both at the protein and at the mRNA-level. (Mol Cell Biochem 262:135–143, 2004)