Altered levels of prothymosin immunoreactive peptide, a growth-related gene product, during liver regeneration after chronic ethanol feeding.

Abstract

Liver regeneration is regulated by the orderly activation of growth-related genes. Although ethanol impairs induction of liver regeneration by partial hepatectomy, we have not identified ethanol-associated differences in the hepatic mRNA levels of several proto-oncogenes, including c-myc, which peaks 3-6 hr post-partial hepatectomy. Prothymosin alpha, a gene encoding a ubiquitous nuclear protein, is activated by c-myc in resting fibroblasts and has been implicated as a regulator of cell proliferation. Prothymosin alpha mRNA levels reportedly increase 12-32 hr post-partial hepatectomy, several hours after c-myc induction. We sought to determine if chronic ethanol intake alters the expected induction post-partial hepatectomy of prothymosin alpha steady-state mRNA expression and protein levels. Comparing rats chronically fed ethanol with pair-fed controls, we found no significant differences in steady-state levels of prothymosin alpha mRNA; however, we did see a delay in the increase of prothymosin immunoreactive peptide in rats chronically fed alcohol. This suggests that the inhibition in protein levels in ethanol fed rats is not due to lower steady-state mRNA levels, but may occur post-transcriptionally. Further data are needed to determine if this finding is important in the inhibition in cell growth following partial hepatectomy in rats chronically fed ethanol.