Cell cycle and organelle enzyme changes in the regenerating liver of the alcoholic rat

Chronic ethanol effect on regenerating post-partial hepatectomy rat liver was studied from 0 to 80 hr to evaluate sequential changes. The rate of restoration in liver mass was comparable between controls (C) and ethanol (E) treated rats. Cell cycle changes included a decrease in magnitude and duration of the early peak in DNA synthesis (24 hr). However, the second peak (40 hr) was increased in magnitude so that the net change was negligible. Histone synthesis increased markedly, whereas thymidine kinase activity was moderately increased. The net effect was an accelerated accumulation of DNA (0.18 mg of DNA/g liver/hr vs 0.29 mg of DNA/g liver/hr; C vs E). The M phase of the cell cycle was initially delayed by ethanol, but once initiated, it exhibited greater numbers of mitoses reaching significance at 72 hr. It is concluded that although ethanol induces multiple changes, the overall process of restoring liver mass and cell number (DNA synthesis) is not impaired.