A patient is found to have a rare disease in which the secretory function of the alpha-cells of the pancreas is impaired. Direct stimulation of which of the following pathways in liver will be impaired?
High-Yield Explanation
Gluconeogenesis is the process of synthesizing glucose or glycogen from noncarbohydrate precursors. The major substrates are the glucogenic amino acids, lactate, glycerol, and propionate. Liver and kidney are the major gluconeogenic tissues; the kidney may contribute up to 40% of total glucose synthesis in the fasting state and more in starvation. Glucagon is a hormone produced and secreted by the alpha-cells of the pancreas in response to decreases in blood glucose. Glucagon and epinephrine, hormones that are responsive to a decrease in blood glucose, inhibit glycolysis and stimulate gluconeogenesis in the liver by increasing the concentration of cAMP. Pentose pathway and citric acid cycle are not directly affected by glucagon. Ref: Bender D.A., Mayes P.A. (2011). Chapter 20. Gluconeogenesis & the Control of Blood Glucose. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.