Glucagon
A) is secreted by the beta cells of the islets of Langerhans
B) is secreted in response to a fall in blood glucose
C) is, in general, antagonistic to all other hormones in terms of metabolic effects
D) increases fat stores by inhibiting the enzyme that catalyzes triglyceride breakdown
E) none of these

Question

Quizplus · Accepted Answer

Glucagon is secreted by the alpha cells of the islets of Langerhans in response to a fall in blood glucose. It is generally antagonistic to insulin in terms of metabolic effects (choice C is partially correct but not comprehensive enough). Glucagon stimulates the breakdown of glycogen into glucose in the liver, raising blood glucose levels (opposite of insulin's effect) and does not directly affect fat stores (choice D is incorrect).