A condition which favors increased ketone body synthesis is

A condition which favors increased ketone body synthesis is Question 5 options: A. increased glycogenolysis in skeletal muscle. B. increased fatty acid synthesis in liver. C. increased lipolysis in adipose tissue. D. decreased gluconeogenesis in liver.

Solution

Choice D is correct.

Reason: Keto-metabolism or ketone body metabolism is a metabolic process involving generation and breakdown of ketone bodies i.e. ketogenesis and ketolysis respectively. Under normal conditions, the balance of ketogenesis and ketolysis is maintained by liver. When a person takes normal diet, the liver utilizes fat as a source of energy and utilizes it for fatty acid synthesis. However, under conditions of fasting, the liver undergoes \"substrate switching\" and this fat is channelized for fatty acid oxidation. This process generates ketone bodies in the body. This is also accompanied with decrease in gluconeogenesis in the liver. This is because when gluconeogenesis is down-regulated in the liver, the primary substrate for ketogenesis i.e. oxalo acetic acid is channelized for generation of glucose in the liver. This depletes the liver of oxalo acetic acid. However, this does not happen under prolonged fasting conditions where this available oxaloacetic acid is converted for ketogenesis in the liver itself. Thus, preferring gluconeogenesis under fasting conditions will be a thermodynamically futile process and instead of it, the liver prefers to perform ketogenesis.