Which hormone is secreted during low blood sugar levels to increase glucose availability?

Glucagon is the hormone that plays a crucial role in increasing glucose availability during periods of low blood sugar levels. When blood glucose levels drop, the pancreas secretes glucagon, which prompts the liver to convert stored glycogen into glucose through a process known as glycogenolysis. This release of glucose into the bloodstream helps to raise blood sugar levels to a normal range, ensuring that the body, particularly the brain, has enough energy to function properly.

While other hormones like insulin, cortisol, and norepinephrine are important in glucose metabolism and overall energy regulation, they function differently. Insulin, for example, is secreted in response to high blood sugar levels and facilitates the uptake of glucose into cells, thereby lowering blood glucose levels. Cortisol has a broader role in stress response and can influence glucose metabolism indirectly, but it does not directly increase glucose availability during low blood sugar. Norepinephrine, while involved in the fight-or-flight response, affects energy metabolism in a different manner and is not specifically responsible for increasing glucose when blood sugar is low.