Fuel utilization across different organs Ketone bodies can be used as fuel in the heart, brain and muscle, but not the liver. They yield 2 guanosine triphosphate (GTP) and 22 adenosine triphosphate (ATP) molecules per acetoacetate molecule when oxidized in the mitochondria. Ketone bodies are transported from the liver to other tissues, where acetoacetate and β-hydroxybutyrate can be reconverted to acetyl-CoA to produce reducing equivalents (NADH and FADH2), via the citric acid cycle. Though it is the source of ketone bodies, the liver cannot use them for energy because it lacks the enzyme thiophorase (β-ketoacyl-CoA transferase). Acetone is taken up by the liver in low concentrations and undergoes detoxification through the methylglyoxal pathway which ends with lactate. Acetone in high concentrations, as can occur with prolonged fasting or a ketogenic diet, is absorbed by cells outside the liver and metabolized through a different pathway via propylene glycol. Though the pathway follows a different series of steps requiring ATP, propylene glycol can eventually be turned into pyruvate.
Fuel utilization across different organs Ketone bodies can be used as fuel in the heart brain and muscle but not the liver They yield 2 guanosine triphosphate (GTP) and 22 adenosine triphosphate (ATP) molecules per acetoacetate molecule when oxidized in the mitochondria Ketone bodies are transported from the liver to other tissues where acetoacetate and β-hydroxybutyrate can be reconverted to acetyl-CoA to produce reducing equivalents (NADH and FADH2) via the citric acid cycle Though it is the source of ketone bodies the liver cannot use them for energy because it lacks the enzyme thiophorase (β-ketoacyl-CoA transferase) Acetone is taken up by the liver in low concentrations and undergoes detoxification through the methylglyoxal pathway which ends with lactate Acetone in high concentrations as can occur with prolonged fasting or a ketogenic diet is absorbed by cells outside the liver and metabolized through a different pathway via propylene glycol Though the pathway follows a different series of steps requiring ATP propylene glycol can eventually be turned into pyruvate