EXPRESSION OF P21(WAF-1 CIP-1) IS SIGNIFICANTLY INDUCED IN THE LIVERSOF LEC RATS WITH CHRONIC LIVER-INJURY/

It is reported that hepatocytes isolated from LEC rats with chronic li ver injury show reduced growth activity in primary culture. To elucida te the molecular basis of this phenomenon, we examined expression of p 21(waf-1/cip-1) and p27, cyclin-dependent kinase inhibitors, by northe rn blot analysis. The expression of p21(waf-1/cip-1) in the LEC rat li ver was 3-fold higher than that of age-matched SD rat liver, while the re was no significant difference in p27 expression level. Western blot analysis also revealed a significant increase in p21(waf-1/cip-1) in the nuclear matrix fraction of the LEC rat liver. Immunohistochemicall y, p21(waf-1/cip-1) was detected in the nuclei of normal LEC rat hepat ocytes, but not in those of hepatocellular carcinoma cells, suggesting selective growth of neoplastic hepatocytes.