Question

Although glucagon is a small polypeptide, it is nevertheless very potent in its regulatory effects. What is the regulatory effect of glucagon?

1) Increases blood glucose levels
2) Decreases blood glucose levels
3) Increases insulin secretion
4) Decreases insulin secretion

Answer 1

Glucagon's regulatory effect is to increase blood glucose levels through glycogenolysis and gluconeogenesis, and its secretion is regulated by a negative feedback mechanism.

Step-by-step explanation:

The regulatory effect of glucagon is to increase blood glucose levels. When blood glucose levels fall, glucagon is released from the alpha cells of the pancreas. It achieves its regulatory effect primarily through two processes: glycogenolysis, which is the breakdown of glycogen into glucose in the liver, and gluconeogenesis, which is the synthesis of glucose from non-carbohydrate sources such as amino acids. Glucagon also promotes lipolysis, which releases fatty acids used for energy, consequently sparing glucose. The increased availability of glucose in the bloodstream provides energy to cells, especially during periods between meals or during increased energy demands. Additionally, glucagon production is part of a negative feedback system, where rising blood glucose levels will inhibit further glucagon release, maintaining homeostasis.