Which mechanism of action explains how glyburide decreases serum glucose levels?

Which mechanism of action explains how glyburide decreases serum glucose levels?

• A. Stimulates the pancreas to produce insulin
• B. Accelerates the liver's release of stored glycogen
• C. Increases glucose transport across the cell membrane
• D. Decreases absorption of glucose from the gastrointestinal system

Answer: (A)

Glyburide lowers serum glucose by increasing insulin secretion from pancreatic beta cells. It binds to a sulfonylurea receptor on these cells, closes ATP-sensitive potassium channels, and causes the cell to depolarize. This depolarization opens voltage-gated calcium channels, calcium enters the cell, and insulin-containing granules are released. The resulting rise in circulating insulin promotes glucose uptake into muscle and fat and reduces hepatic glucose output, leading to lower blood glucose levels. This mechanism is different from actions that would directly release stored glycogen from the liver, move glucose across cell membranes on its own, or reduce glucose absorption in the gut.

Glyburide lowers serum glucose by increasing insulin secretion from pancreatic beta cells. It binds to a sulfonylurea receptor on these cells, closes ATP-sensitive potassium channels, and causes the cell to depolarize. This depolarization opens voltage-gated calcium channels, calcium enters the cell, and insulin-containing granules are released. The resulting rise in circulating insulin promotes glucose uptake into muscle and fat and reduces hepatic glucose output, leading to lower blood glucose levels.

This mechanism is different from actions that would directly release stored glycogen from the liver, move glucose across cell membranes on its own, or reduce glucose absorption in the gut.