Correct Answer: (a) Glucose level in liver diminished
Solution:Glucose level in liver diminished on fasting for more than 10 days. Researchers found that during fasting, the liver is busy producing glucose from its stored glycogen. In the absence of dietary sugars and carbohydrates, glucose is obtained from the breakdown of stored glycogen. Glycogen is a readily-accessible storage form of glucose, stored in notable quantities in the liver and skeletal muscle. When the glycogen reserve is depleted, glucose can be obtained from the breakdown of fats from adipose tissue. Fats are broken down into glycerol and free fatty acids, with the glycerol being turned into glucose in the liver via the gluconeogenesis pathway. When even the glucose made from glycerol reserves start declining, the liver starts producing ketone bodies. Ketone bodies are short-chain derivatives of the free fatty acids, and can cross the blood-brain barrier, meaning they can be used by the brain as an alternative metabolic fuel. After 2 or 3 days of fasting, the liver begins to synthesize ketone bodies from precursors obtained from fatty acid breakdown. During starvation, following complete hepatic glycogen depletion, amino acids become the major source for glucose homeostasis. After several days of fasting, all cells in the body begin to break down protein. This releases amino acids into the bloodstream, which can be converted into glucose by the liver. As starvation progresses, gluconeogenesis diminishes in the liver but increases in the kidney as the need for ammonia excretion increases.
