Fuller S J, Gaitanaki C J, Sugden P H
Department of Cardiac Medicine, National Heart and Lung Institute, University of London, U.K.
Biochem J. 1989 Apr 1;259(1):173-9. doi: 10.1042/bj2590173.
Increasing the extracellular pH over the range pH 7.4-8.9 stimulated protein synthesis by about 60% in the rat heart preparation anterogradely perfused in vitro. Protein degradation was inhibited by this pH increase. The magnitudes of the effects at pH 8.9 on protein synthesis and degradation were similar to those of high concentrations of insulin. Cardiac outputs were increased, as were cardiac phosphocreatine contents, indicating that the alterations in extracellular pH did not adversely affect the physiological viability of the preparation. ATP contents were unaltered. The creatine kinase equilibrium was used to assess the magnitude of the change in intracellular pH induced by these treatments. The increase in intracellular pH was about 0.2 for a 1-unit increase in extracellular pH. Thus small changes in intracellular pH have dramatic effects on cardiac protein turnover.
在体外顺行灌注的大鼠心脏标本中，将细胞外pH值从7.4提高到8.9，可刺激蛋白质合成增加约60%。这种pH值的升高抑制了蛋白质降解。pH 8.9时对蛋白质合成和降解的影响程度与高浓度胰岛素的影响相似。心输出量增加，心肌磷酸肌酸含量也增加，这表明细胞外pH值的改变并未对标本的生理活力产生不利影响。ATP含量未改变。利用肌酸激酶平衡来评估这些处理引起的细胞内pH值变化幅度。细胞外pH值每升高1个单位，细胞内pH值升高约0.2。因此，细胞内pH值的微小变化对心脏蛋白质周转有显著影响。
