PROTEIN-SYNTHESIS IS INVOLVED IN THE MODULATION OF THE LEVEL OF THE PHOSPHOENOLPYRUVATE CARBOXYKINASE MESSENGER-RNA BY CHANGES IN CELL-VOLUME IN ISOLATED RAT HEPATOCYTES

The mechanism of action of hydration state was studied on phosphoenolp yruvate carboxykinase (PCK) gene expression in isolated rat hepatocyte s. Hypoosmolarity decreased the level of the PCK mRNA after a lag peri od of about 60 min, The decreasing effect of hypoosmolarity was totall y blocked by inhibitors of both protein synthesis and gene transcripti on. Moreover, hypoosmolarity specifically increased the synthesis of a 45000 M-r protein, which decreased in the presence of inhibitors of t ranscription, A close relationship between the synthesis of the 45 000 M-r protein and the decrease in the PCK mRNA level was observed, sugg esting that this protein might potentially be involved in the regulati on of the level of the PCK mRNA by cell swelling. (C) 1998 Federation of European Biochemical Societies.