Pancreatic oxidation of glucose results in increased release of insulin. This mechanism is referred to as glucose-stimulated insulin secretion (GSIS). A defect in which of the following proteins would be expected to exert the greatest negative effect on GSIS?
A) AMPK
B) ABCC8
C) glucokinase
D) GLUT2
E) KCNJ11

Question

Quizplus · Accepted Answer

Glucokinase acts as a glucose sensor in pancreatic beta cells, initiating the glycolytic pathway that leads to ATP production and subsequent insulin release. A defect in glucokinase would severely impair glucose-stimulated insulin secretion.  Glucose uptake into pancreatic b-cells involves the constitutive transporter GLUT2 which essentially transports glucose via a concentration gradient. Once inside the cell, in order to be metabolized, glucose has to be phosphorylated by glucokinase. This not only primes the glucose for oxidation but also traps it inside the b-cell. Lack of glucokinase would result in no oxidation of glucose so there would be no alteration in the ATP/ ADP ratio which is important in the process of GSIS.

Pancreatic Oxidation of Glucose Results in Increased Release of Insulin