What regulates ketone body synthesis?
The primary regulator of ketone body synthesis is fatty acid availability. When hormonal conditions (e.g., high glucagon, low insulin) cause fatty acid concentration in the plasma to be high, malonyl CoA concentration in the liver cytoplasm is low (because acetyl CoA carboxylase is in the less active phosphorylated state). Fatty acyl CoA can enter the mitochondria at a high rate (because there is no inhibition of CAT I), and beta-oxidation proceeds at a high rate. The ensuing high mitochondrial concentration of acetyl CoA results in active ketone body synthesis.
