Final answer:
Glucagon is known as the hyperglycemic factor because it raises blood glucose levels by stimulating glycogenolysis and gluconeogenesis, counteracting insulin's effects.
Step-by-step explanation:
Glucagon is often referred to as a hyperglycemic factor due to its role in increasing blood glucose levels. This hormone, which consists of 29 amino acids, is secreted by the alpha cells of the islets of Langerhans in the pancreas. When blood glucose levels fall, such as during periods of fasting, glucagon is released to stimulate the process known as glycogenolysis, where glycogen stored in the liver is broken down into glucose. Additionally, it is involved in gluconeogenesis, the synthesis of glucose from non-carbohydrate substrates like amino acids. Functioning in opposition to insulin, glucagon helps maintain blood glucose homeostasis, and an imbalance in its level could lead to conditions such as diabetes mellitus or hypoglycemic shock.