Increased formation of ketone bodies during fasting is a result of:
Free fatty acids bound to albumin are increased as a result of an increased activity of Hormone sensitive lipase in adipose tissue as this enzyme breaks TG into glycerol & fatty acids. These fatty acids are taken up by liver. b-oxidation of these fatty acids in liver provides the acetyl CoA for ketogenesis. Hepatic ketogenesis is also stimulated by elevated levels of glucagon during fasting.
Decreased level of circulating glucagon
Decreased formation of Acetyl CoA in the liver
Increased levels of free fatty acids in blood
Inhibition of b-oxidation of fatty acids in liver
Fuel in Fed, Fasting and Starvation