Mechanism of action Insulin is a protein normally produced in the pancreas which regulates metabolic processes throughout the body. The primary role of insulin is to increase the metabolism of glucose, storage of energy in adipose tissue, and decrease the body's own production of glucose. Pharmacokinetics The half life of endogenous insulin once it<unk> rs the bloodstream is 4 to 6 minutes. This allows the endocrine system to rapidly adapt to changing conditions within the body. Exogenous insulin, however, would not be effective with a short half life, as it would require continuous injection or infusion to have the desired effect. While it is difficult to change the rate at which the protein is metabolized in the bloodstream, it is possible to alter how fast the protein is absorbed from the site of injection in various ways.<unk>  was formulated by the addition of zinc to the crude porcine and bovine insulin extracts, which causes the insulin protein to form larger crystals which dissolve into the body slower upon injection. This means that while the insulin in the bloodstream is still metabolized in 4–6 minutes, more insulin is continually being absorbed from the dose injected for hours after administration. Compared to NPH insulin, another intermediate acting insulin, up to 40% of the dose of<unk>  may remain unabsorbed for over 24 hours after administration. The variation in absorption between doses in the same patient of<unk>  is comparable to that of insulin NPH. The distribution of insulin is not well understood, but it is known that it is heavily bound to receptors throughout the body (approximately 80% to receptors on liver cells) and metabolized in large part by phase one processes in the liver. Of the approximately 71-minute estimated lifetime of an insulin molecule, over 60 minutes is spent attached to a liver receptor. In addition, circulating unbound insulin is excreted and reabsorbed by the kidneys and broken down in the lysosomes. The remainder of metabolism of insulin molecules is via intracellular proteolysis via insulysin and related enzymes.
Lente insulin
Insulin aspart
Regular insulin
Insulin detemir
Insulin glulisine
Ultralente insulin
Insulin glargine
Insulin degludec