The 3 carbons at the w -end of the odd chain fatty acid , therefore, can form glucose in the liver. An isomerase and a reductase are required for the oxidation of unsaturated fatty acids. Acetoacetate and 3-hydroxybutyrate are normal fuels of respiration and are quantitatively important as sources of energy. Under fasting , the liver is synthesizing glucose . NADH produced by b -oxidation drives oxaloacetate to malate .
Less oxaloacetate is available, acetyl CoA accumulates .
Two molecules of acetyl CoA react to form acetoacetyl CoA . Oxidation of Ketone Bodies During starvation, ketone bodies enter brain cells. Although the liver produces ketone bodies, it does not utilize them because this thiotransferase enzyme is not present in sufficient quantity. Significance of Ketone Body Metabolism During starvation, the brain can oxidize ketone bodies , reducing its need for glucose . Gluconeogenesis decreases in the liver and muscle protein is spared .