Studies on hepatic gene expression in different liver regenerative models

We have investigated the expression of several growth-related genes in the liver after partial hepatectomy in three experimental models: normal, Dexam ethasone-pretreated, and hypophysectomized rats. Dexamethasone and hypophys ectomy resulted in a delay in the peak of cell replication in 6 and 18 h, r espectively, when compared to the normal animals. TGF alpha mRNA expression was shifted together with the DNA synthesis, but the expression of c-myc, c-fos, c-jun, HGF, TGF beta 1, IL1 beta did not delay, This result suggests that liver-derived TGF alpha but not the other factors are important in th e timing of the proliferative response after partial hepatectomy. (C) 2000 Academic Press.