Ketone Bodies Metabolism – This is the video on ketone body synthesis, utilization of ketone bodies, regulation of ketone bodies metabolism and note on ketosis.
Acetoacetate, β-hydroxybutyrate and acetone are known as ketone bodies
Acetoacetate and β-hydroxybutyrate are interconverted by the mitochondrial enzyme β-hydroxybutyrate
Acetoacetate continually undergoes spontaneous nonenzymatic decarboxylation to yield acetone
The concentration of total ketone bodies in the blood of well-fed condition does not normally exceed 0.2 mmol/L.
Liver is the only organ that synthesizes ketone bodies. and transferred to other organs as fuel
The synthesis of ketone bodies occurs in mitochondria of hepatic cells
Utilization of Ketone Bodies
The site of production of ketone bodies is the liver.
But the liver cannot utilize ketone bodies because it lacks particular enzyme CoA-transferase which is required for activation of ketone bodies
Rbc exclusively utilize glucose.
Significance of Ketogenesis
Ketogenesis is a mechanism that allows the liver to oxidize increasing quantities of fatty acids.
During deprivation of carbohydrate (starvation & diabetes mellitus) acetoacetate and β-hydroxybutyrate serve as alternative source of energy for extra hepatic tissues
In prolonged starvation 75% of the energy needs of the brain are supplied by ketone bodies reducing its need for glucose.
When the rate of formation of the ketone bodies by liver exceeds the capacity of the peripheral tissues to use them up, their levels begin to rise in blood.
An increase in concentration of ketone bodies in blood is called ketonemia and eventually leads to excretion of ketone bodies into the urine called ketonuria.
The overall condition (ketonemia and ketonuria) is called ketosis.