What is insulin?

• A. A hormone that increases blood sugar
• B. Produced by liver
• C. A digestive enzyme
• D. A storage hormone released by pancreas to decrease blood sugar

Answer: (D)

Insulin is a hormone secreted by the pancreas that lowers blood sugar. It signals cells, especially in muscle and fat tissue, to take up glucose from the bloodstream and promotes storage of excess glucose as glycogen in the liver and muscles and as fat in adipose tissue. This action helps restore blood glucose toward a normal level after a meal. It’s not produced by the liver, nor is it a digestive enzyme, and its role is to reduce, not raise, blood sugar. So describing it as a storage hormone released by the pancreas to decrease blood sugar best captures its function.