FUNCTIONS -

(a) It is antagonistic to glucagon. Insulin decreases the level of glucose in the blood. It acts by increasing the rate at which glucose is transported out of the blood and into cells and by stimulating muscle cells to take up sugar from the blood and convert it to glycogen.

• Like glucagon, insulin is primarily regulated by feedback from the blood glucose concentration. When the blood sugar level drops, the secretion of insulin is suppressed. When the blood sugar level increases, the secretion of insulin is stimulated.

(b) It promotes protein synthesis in tissue from amino acids.

(c) Insulin reduces catabolism of proteins. It is an anabolic hormone.

(d) It increases the synthesis of .fat in the adipose tissue from fatty acids. (e) Insulin reduces the breakdown and oxidation of fat.

Target Cells. Insulin acts on the cells of the liver muscles and adipose tissue.