Effect of malotilate (diisopropyl 1,3-dithiol-2-ylidenemalonate) on the protein synthesis in rat liver.

The effect of malotilate (diisopropyl 1,3-dithiol-2-ylidenemalonate) on the protein synthesis in rat liver was studied in vivo and in vitro. Oral administration of malotilate to rats caused an increase in the protein and RNA contents of the liver and lef to an acceleration of 14C-leucine incorporation into microsomal and cytosol proteins. In a cell-free system, the protein synthesis was enhanced by treatment with malotilate, and an unknown factor(s) which participates in the protein synthesis was found in the cytosol fraction prepared from malotilate treated livers. These results suggest that malotilate is a new type of inducer for protein synthesis. On the basis of the observations obtained in the present study, a hypothesis can be formulated that malotilate enhances liver protein synthesis by accelerating RNA synthesis and/or increasing the transport of RNA from nuclei to cytosol in rat liver.