EFFECT OF XANTHINES AND SOME DERIVATIVES ON PROTEIN-METABOLISM IN ISOLATED PARENCHYMAL RAT-LIVER CELLS

(1) Isolated parenchymal rat liver cells were incubated in Krebs-Henseleit buffer containing 0.5% gelatine. (2) Xanthines (caffeine, theophylline, theobromine, paraxanthine) and some derivatives (IBMX, aminophylline, proxiphylline) all inhibited the incorporation of [14C]valine into proteins in the medium and albumin secretion. (3) The incorporation into liver cell proteins was only significantly inhibited by IBMX, caffeine and theophylline. (4) Xanthine and metabolites of xanthines had no or only slight effect on the variables mentioned above. (5) The inhibitory effect of xanthines and their derivatives on protein metabolism could not be explained by an increased level of cyclic AMP, a decreased secretion of proteins from the liver cells, an inhibition of amino acid transport, an increased degradation of proteins or an effect at the transcription level. (6) The results are compatible with an effect on protein synthesis on the translation level. © 1979.