What hormone is released by the pancreas in response to low blood glucose levels?

The hormone that is released by the pancreas in response to low blood glucose levels is glucagon. When blood sugar levels drop, the pancreas secretes glucagon to stimulate the liver to release stored glucose (glycogen) into the bloodstream. This process is crucial for maintaining stable blood glucose levels and ensuring that the body has adequate energy supply, especially during fasting or prolonged periods without food.

In contrast, insulin, secreted when blood sugar levels are high, serves to lower blood glucose by facilitating the uptake of glucose by cells. Cortisol is a stress hormone that can raise blood glucose levels by promoting gluconeogenesis in the liver. Adrenaline, while also increasing blood glucose levels, mostly acts in acute stress situations to ensure immediate energy availability.

Thus, glucagon specifically plays a vital role in the regulation of blood glucose levels when they are low, making it the correct response to the question.