In: Anatomy and Physiology
1. If muscle-derived amino acids are used for gluconeogenesis, why does the rate of glucose output by the liver slow during prolonged starvation?
Except 2 amino acids all other amino acids can participate in gluconeogenesis. During starvation time gluneogenesis is mostly dependent. But the major factor is that the muscle lactate is used to form the glucose in liver. It will be available, because when muscle works lactic acid is getting accumulated. But when we deal about muscle derived amino acid among the amino acids only alanine and glutamine will participate in the gluconeogenesis. These amino acid content will reduce as the starvation starts. The muscles will need this amino acid content for their strength. The content of these amino acids is much less compared to the lactate. These amino acids initially converts to alpha ketoacid to form glucose. So as the amino acid is less than lactate the glucose produced will also reduce in the liver. If the amino acids are used it is necessary to replace that with protein and the protein won't breakdown to give these amino acids. So this all affect the rate of glucose formed.