Interference by ethanol of coupling between gluconeogenesis and ureagenesis from proline in isolated hepatocytes.

Proline stimulated equally the production of glucose and urea by isolated hepatocytes. Ethanol suppressed glucose production much more strongly than urea synthesis. The proline-derived carbon not reaching glucose was found as lactate. Inhibition of phosphoenolpyruvate synthesis with 3-mercaptopicolinate blocked gluconeogenesis, but was without effect on lactate production. Acetate was formed from endogenous sources, as well as from ethanol. Its accumulation from ethanol was enhanced both by proline and lactate. The differential effect of ethanol on gluconeogenesis and ureagenesis appears to be related to its effect on the redox state of the cell.