Which hormone promotes cellular uptake of glucose, thereby lowering blood sugar?

• A. Glucagon
• B. Insulin
• C. Epinephrine
• D. Cortisol

Answer: (B)

Insulin promotes cellular uptake of glucose, which lowers blood sugar. When blood glucose rises, insulin is released from pancreatic beta cells. It binds to receptors on muscle and fat cells and triggers a signaling cascade that moves GLUT4 glucose transporters to the cell surface, allowing glucose to enter the cells more efficiently. Inside the cells, glucose is used for energy or stored as glycogen in the liver and muscles, and as fat in adipose tissue. This uptake directly reduces the amount of glucose circulating in the bloodstream.

Other hormones like glucagon, epinephrine, and cortisol tend to raise blood sugar by promoting glucose production in the liver or reducing uptake in certain tissues, rather than increasing cellular glucose uptake. So insulin is the hormone that best fits the description.