Metabolic fate of endotoxin and blood tumour necrosis factor levels in rats with acute and chronic alcohol loading.

To investigate the metabolic fate of endotoxin in alcoholics and its possible relationship to cytokines and liver injury, we administered a low-dose radiolabelled endotoxin to rats given alcohol in various conditions and studied the organ distribution of endotoxin and measured plasma levels of tumour necrosis factor (TNF). In the chronic alcohol-fed rats (Lieber-DeCarli liquid diets for 6 weeks) 3H-endotoxin was rapidly cleared by the liver and excreted into faeces. However, the endotoxin clearance was decreased after an acute ethanol load to rats (5 mg/g body wt ethanol i.p.) or in the chronic ethanol-fed rats with an additional 5 mg/g body wt ethanol load. Plasma TNF was not elevated in the control or in the acute ethanol load rats, slightly elevated in the chronic ethanol-fed rats and markedly elevated in the chronic ethanol-fed rats with an additional high-dose ethanol load. Serum GPT was elevated only in the chronic ethanol-fed rats with an additional high-dose ethanol. In conclusion, an additional administration of a high dose ethanol to chronic alcohol-fed rats led to decrease of endotoxin clearance and elevation of plasma TNF, which may play an important role in the pathogenesis of alcoholic hepatitis.