Which hormone is secreted by the pancreas?

The hormone secreted by the pancreas that plays a crucial role in regulating blood glucose levels is glucagon. This hormone is produced by the alpha cells of the pancreatic islets and functions primarily to increase blood sugar levels when they fall too low. It stimulates the liver to convert stored glycogen into glucose, which is then released into the bloodstream, ensuring that the body has a continuous energy supply.

Insulin, while also secreted by the pancreas (specifically by the beta cells), operates in opposition to glucagon by lowering blood sugar levels following meals. Cortisol is produced by the adrenal glands and plays a different role, primarily in metabolism and the stress response, while adrenaline (also produced by the adrenal glands) is involved in the body's fight-or-flight response. Thus, glucagon is the specific hormone associated with the pancreas that directly influences blood sugar levels.