Effects of ethanol administration on hepatocellular ultrastructure of regenerating liver induced by partial hepatectomy

Acute ethanol administration partially inhibits DNA and protein syntheses d uring liver regeneration (LR) induced by partial hepatectomy (PH) in rats. Previous findings that the magnitude of ethanol's deleterious effects on LR are related to the route and timing of its administration led us to perfor m studies at the ultrastructural level, comparing ethanol effects on PH-ind uced LR, as a consequence of its administration route. PH promoted alterati ons on the endoplasmic reticulum and mitochondria, accompanied by decreased glycogen and increased lipid content in cytoplasm. Structural nuclear and nucleolar activities were also evident. Intragastric ethanol administration practically abolished the adaptative changes found in PH-promoted regenera ting hepatocytes, whereas its administration through the intraperitoneal ro ute induced later ultrastructural modifications, indicating cellular prolif eration. These results suggest that ethanol, under certain conditions, coul d stimulate liver proliferation triggered by PH. The mechanism underlying t his surprising effect of ethanol on LR remains to be elucidated, However, i t is suggested that an altered ethanol metabolism by rats subjected to PH c ould be involved.