Which hormone produced by the pancreas is responsible for triggering the conversion of glycogen into glucose in the liver?

The hormone produced by the pancreas that triggers the conversion of glycogen into glucose in the liver is glucagon. This process, known as glycogenolysis, occurs when the body needs to increase blood glucose levels, typically when they drop between meals or during periods of physical activity.

Glucagon is released by the alpha cells of the pancreas when blood glucose levels are low. It binds to receptors on liver cells, initiating a signaling cascade that leads to the breakdown of glycogen, which is a stored form of glucose. The glucose that is released into the bloodstream then helps to restore blood glucose levels to a normal range, providing energy for metabolism and functioning of various tissues, particularly during times of fasting or increased energy demand.

Insulin, on the other hand, has the opposite effect, promoting the storage of glucose as glycogen in the liver and facilitating the uptake of glucose by cells when blood sugar levels are high. Hemoglobin is a protein in red blood cells responsible for oxygen transport and does not play a role in glucose metabolism. Growth hormone influences growth and metabolism but does not directly regulate glycogen to glucose conversion. Thus, glucagon is correctly identified as the hormone responsible for stimulating glycogen breakdown into glucose in the liver.