Which metabolic process is stimulated by glucagon during fasting?

During fasting, glucagon plays a critical role in maintaining blood glucose levels by stimulating gluconeogenesis, the metabolic process that generates glucose from non-carbohydrate substrates. Glucagon is secreted by the alpha cells of the pancreas when blood glucose levels are low, signaling the liver to produce and release glucose into the bloodstream.

Gluconeogenesis primarily occurs in the liver and involves converting amino acids, lactate, and glycerol into glucose. This process is essential during fasting because the body needs to ensure a continuous supply of glucose for cells that require it, such as red blood cells and brain cells, which depend on glucose as a primary energy source.

Additionally, glucagon influences other processes like fatty acid oxidation and ketogenesis to provide energy during prolonged fasting; however, its direct stimulation of gluconeogenesis is what primarily addresses the need for maintaining glucose levels. Thus, the focus on gluconeogenesis during fasting is crucial for energy homeostasis and metabolic balance.