Final answer:
High concentrations of glucagon, produced by alpha cells in the pancreas, promote lipolysis and gluconeogenesis to increase blood glucose levels during periods of low energy intake. Glucagon stimulates the breakdown of stored fats into glycerol and fatty acids, and aids in the conversion of amino acids to glucose in the liver.
Step-by-step explanation:
High concentrations of glucagon (a polypeptide molecule produced by alpha cells to maintain normoglycemia during periods of fasting) activate adipose cell lipase to break down triglycerides into glycerol and fatty acids. In addition, high levels of amino acids (products of proteolysis) activate this hormone to increase transport to the liver for gluconeogenesis synthesis.
Glucagon is a crucial hormone in the regulation of glucose levels in the blood, particularly during times when food intake is low, or the body needs additional energy. It plays an antagonistic role to insulin, and both are part of a negative-feedback system that stabilizes blood glucose levels. When blood glucose levels fall, glucagon is secreted by the alpha cells in the pancreas, promoting glycogenolysis in the liver, gluconeogenesis, and lipolysis in adipose tissues, leading to increased blood glucose levels.