Final answer:
Glucagon triggers the breakdown of triglycerides into glycerol and free fatty acids through lipolysis when blood sugar levels are low. It also promotes glycogenolysis and gluconeogenesis to maintain normal blood glucose levels, working in balance with insulin.
Step-by-step explanation:
Lipolysis and Glucagon's Role in Blood Sugar Regulation
When blood sugar levels drop, such as during periods when food intake is not sufficient or during strenuous activities, the hormone glucagon plays a critical role in maintaining normal glucose levels. Glucagon is secreted by the alpha cells of the pancreas and prompts the liver to break down stored glycogen into glucose, a process known as glycogenolysis. Additionally, glucagon facilitates the breakdown of triglycerides into glycerol and free fatty acids in adipocytes through the action of hormone-sensitive lipase.
The process by which triglycerides are broken down is called lipolysis. Fatty acids released from this process can be transported in the blood to various tissues for energy, while glycerol can be utilized by the liver and kidneys to synthesize new glucose through gluconeogenesis. This gluconeogenic pathway is particularly important during extended periods of fasting, where muscle proteins and other substrates like lactate can additionally provide carbon skeletons for glucose production.
Both insulin and glucagon work together in a delicate balance to maintain homeostatic glucose levels, with insulin lowering blood glucose and glucagon raising it. The negative feedback mechanism helps to ensure that glucagon secretion is inhibited once the blood glucose levels are restored to their normal range, thus preventing hyperglycemia.