Moderate and large doses of ethanol differentially affect hepatic protein metabolism in humans

The intake of ~70 g of alcohol impairs liver protein metabolism in healthy humans. To establish the threshold at which alcohol impairs hepatic protein metabolism in humans we compared the effects of 500 mL of water (control study), 300 (28.4 g ethanol) or 750 mL (71 g ethanol) of table wine on hepatic protein metabolism in three groups of healthy nonalcoholic volunteers. Hepatic protein metabolism was estimated (L-[1-¹⁴C]leucine infusion) by measuring the fractional secretory rates of albumin and fibrinogen during the overnight postabsorptive state (basal) and the subsequent administration of water or two different amounts of wine (300 or 750 mL) given with a liquid glucose-lipid-amino acid meal. During the meal, water did not affect fibrinogen fractional secretory rate and increased albumin fractional secretory rate by ~50% (P < 0.01). The 300 mL of wine increased albumin secretory rate by only ~20% (P < 0.01 vs. basal, P < 0.04 vs. water) and did not affect fibrinogen secretory rate. The 750 mL of wine profoundly impaired hepatic protein metabolism, decreasing the fractional secretory rates of albumin (P < 0.01 vs. water and 300 mL wine) and fibrinogen (P < 0.04 vs. water and 300 mL of wine) below the postabsorptive values. These results demonstrate that a moderate dose of alcohol (28 g, ~2 drinks) slightly affects postprandial hepatic protein metabolism by blunting the meal-induced increase in albumin synthesis, whereas it does not interfere with fibrinogen synthesis as do higher doses.