Ethanol Metabolism and Gluconeogenesis

Ethanol strongly inhibits gluconeogenesis and can bring about hypoglycemia, a potentially dangerous decrease in blood glucose levels. Ethanol metabolism occurs primarily in the liver. The reaction, catalyzed by alcohol dehydrogenase, is shown as follows:

> Ethanol + NAD+ <=> Acetaldehyde + NADH + H+

The NADH produced in this reaction shifts the equilibrium in the liver cytosol of the lactate dehydrogenase from pyruvate formation to lactate synthesis.

The NADH also favors reduction of oxaloacetate to malate in the reaction catalyzed by malate dehydrogenase, making less oxalacetate available for gluconeogenesis. The resulting hypoglycemia can affect the part of the brain concerned with temperature regulation and the body temperature can fall by as much as 2C. Thus, feeding alcohol to people suffering from hypothermia is counterproductive. Metabolically speaking, glucose would be far more effective in raising body temperature.

See also: Relationship of Gluconeogenesis to Glycolysis, Gluconeogenesis, Lactate Dehydrogenase, Pyruvate, Lactate, Oxaloacetate, L-Malate.