Light ethanol consumption enhances liver regeneration after partial hepatectomy in rats

Background & Aims: The effects of "social drinking" on the liver have yet t o be fully documented. The aim of this study was to document the effects of daily light, moderate, and heavy ethanol exposure on hepatic regenerative activity in the rat. Methods: Adult male Sprague-Dawley rats underwent dail y gavages with 1.0 (light), 2.0 (moderate), or 4.0 (heavy) g/kg of ethanol or tap water (controls) for 30 days before 70% partial hepatectomy (PHx). H epatic regenerative activity was then documented on days 1, 3, 5, and 7 aft er PHx. Results: Compared with controls, restitution of liver mass, [H-3]th ymidine incorporation, and proliferating cell nuclear antigen expression we re decreased in the heavy (-10%, -60%, and -36%, respectively), unchanged i n the moderate (-4%, -8%, and -16%, respectively), and increased in the lig ht (+6%, +38%, and +29%, respectively) ethanol groups. Messenger RNA differ ential display of resected livers at PHx identified a band present only in the light ethanol group that encodes a unique 47-kilodalton protein with gr owth-promoting features designated light ethanol-induced stimulatory protei n. Conclusions: The results indicate that light ethanol consumption enhance s hepatic regenerative activity after PHx in rats. Further studies are requ ired to determine the mechanism involved and whether social drinking has be neficial or adverse effects on the natural history of acute or chronic live r disease in humans.