Question

Which of the following statement is correct regarding glucagon hormone?
A) It has the opposite effect to that of insulin.
B) It converts glucose to glycogen.
C) It is given to diabetic patients.
D) It is formed by P-cells of the pancreas.

Answer 1

Hint Glucagon is a small polypeptide hormone with Molecular weight of 3485Da. It is produced by alpha cells of the pancreas, and also by GIT. About one-third of glucagon is delivered to GIT. It is produced as preproglucagon and like insulin is secreted in portal circulation It is degraded by the liver and kidneys. Glucagon binds to its membrane receptor in hepatocytes and activates adenylate cyclase.
Complete Step-by-step answer:
Glucagon is catabolic and causes effects that are usually opposite to insulin. Effectively, it causes the mobilization of carbohydrates, fats, and proteins. Glucagon causes glycogenolysis in the liver. In this, liver cells increase their rate of amino acid uptake and convert most of them to glucose. Glucagon is lipolytic and it increases the expression of lipases, e.g.triglyceride lipase.
Glucagon in very high concentrations also acts to:- enhance heart strength, enhanced blood flow in kidneys, enhanced bile secretion, and inhibition of gastric acid secretion.
Glucagon inhibits protein synthesis and increases protein degradation. Alpha cells of the pancreas secrete glucagon. It is released when the glucose level is low. It initiates the breakdown of glycogen and synthesis in the liver by increasing blood glucose levels.
Its effect opposes the effect of insulin as it is released during high blood glucose levels.
Hence the correct answer is option A.
Note: Glucagon secretion is stimulated by hypoglycemia, a decrease in acids, an increase in amino acids in circulation, and sympathetic stimulation. Glucagon secretion is inhibited by hyperglycemia, an increase in blood fatty acids, somatostatin, and secretion.