A 25-year-old woman presents with intermittent symptoms of sweating, palpitations, and hunger. During each episode, her glucose level is less than 40 mg/dL. Her insulin level is low and glucagon level is high. Which of the following best describes the hormone function of glucagon?

This person has either fasting or reactive hypoglycemia. Glucagon exerts a marked effect on carbohydrate, fat, and lipid metabolism, and increases cAMP in many tissues. It is the first counterregulatory hormone to respond to hypoglycemia, and it does this by increasing glycogenolysis and gluconeogenesis. Glucagonomas of the pancreas present with features such as mild diabetes mellitus (DM), psychiatric disturbances, diarrhea, venous thromboses, and skin findings (necrolytic migratory erythema).