Question 210

Question:

A 52-year-old man with recently diagnosed type 2 diabetes mellitus comes to the physician for a follow-up examination. Physical examination shows no abnormalities. Laboratory studies show an increased hemoglobin A1c despite patient compliance with diet and exercise recommendations. Treatment with a sulfonylurea is started. Which of the following is most likely to occur in this patient?

Correct Answer: E.  Increased secretion of insulin from the pancreas

Sulfonylureas increase the secretion of insulin from pancreatic beta cells (choice E) by binding to ATP-dependent potassium channels causing an inhibition of the outflux of potassium. This causes a depolarization of the cell membrane, which opens voltage-dependent calcium channels and stimulates secretion of insulin-containing granules. In contrast, sulfonylureas do not decrease the secretion of insulin from the pancreas (choice B).
Changing the amount of glucose produced by the liver (choices A and D) is also not the mechanism of action of sulfonylureas. Metformin is an example of a drug that can decrease the amount of glucose produced by the liver.
Sulfonylureas also do not decrease the speed of carbohydrate absorption from the intestines (choice C).