抄録
In this review, we describe two kinds of substances, liver tumor promoters [phenobarbital and barbital] and a glutathione-related tripeptide [S- (1,2dicarboxyethyl)glutathione (DCE-GS)], which induce DNA synthesis in primary cultured rat hepatocytes in the presence of epidermal growth factor (EGF). The two promoters, phenobarbital and barbital, enhanced DNA synthesis in suckling rat hepatocytes which seems to be stimulated by autocrine growth factor(s). On the other hand, phenobarbital suppressed DNA synthesis in adult rat hepatocytes in the absence of growth factors such as insulin and EGF, but enhanced DNA synthesis in the cells stimulated by these growth factors. The tripeptide DCE-GS, which is mainly synthesized in the liver, showed no effect on DNA synthesis in adult rat hepatocytes by itself, but significantly enhanced DNA synthesis in the cells when added simultaneously with EGF. The DCE-GS level was increased in the regenerating rat liver, reaching a maximal level (4.7-fold) on day 2, and reverted to the normal level within 1 week. The time courses of the increase in DCE-GS level and DNA synthesis in the regenerating rat liver closely correlated to each other. These findings probably indicate that the intrinsic tripeptide DCE-GS is closely related to liver regeneration.
