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Aspart insulin

β2 -agonists

insulin and p. 333


insulin and p. 333

in insulinomas p. 359

Detemir insulin

Glargine insulin

Glucagon p. 335

insulin and p. 333, 335

Gluconeogenesis p. 76

in insulin deficiency p. 352


insulin and p. 335

Glulisine insulin

Glycogen p. 84

insulin and p. 333


in insulin deficiency p. 352

Insulin p. 335

anabolic effects of p. 333

deficiency in p. 352

diabetic ketoacidosis p. 357

for HHNS p. 357

fructose bisphosphatase-2 and p. 74

GIP effect on p. 380

glucagon and p. 335

glycogen regulation p. 71, 84

hypokalemia from p. 614

in pregnancy p. 333

production of p. 339

secretion of p. 335

signaling pathways for p. 353

somatostatin and p. 380

somatostatinomas and p. 357


insulin and C-peptide in p. 333

Insulin preparations p. 360


insulin deficiency p. 352


insulin and p. 335

in insulin deficiency p. 352

Lispro insulin

Osmotic diuresis

insulin deficiency/insensitivity p. 352

Plasma osmolality

insulin deficiency/insensitivity p. 352

Pregnancy p. 657

insulin in p. 333

Protein synthesis p. 184, 198

insulin and p. 335


in insulin deficiency p. 352

Regular insulin

Sulfonylureas p. 361

insulin and p. 333


insulin and p. 333

Tyrosine kinase

insulin and p. 333


Insulin is a type of peptide hormone that reduces the amount of glucose in the blood. It is produced in the pancreas by beta cells. These cells are found within clusters of endocrine cells called the Islets of Langerhans, which are distributed across the pancreas. If the body is unable to produce enough insulin, then insulin therapy is used to keep the blood glucose low.

Insulin’s main function is to facilitate the transport of glucose from the blood into the various insulin-responsive tissues like muscle cells and adipose tissue. This hormone binds to insulin receptors on the surface of the cell membrane. Now, these receptors have two alpha and two beta subunits. Alpha subunits are located outside of the cell and they bind insulin; while two beta subunits are located within the cell and they have tyrosine kinase activity which carries signals into the cell. Once stimulated, insulin receptors cause intracellular storage vesicles, which contain glucose transport proteins called GLUT4, to fuse with the cell membrane. Next, the GLUT4 proteins embed themselves into the membrane and allow glucose to move into the cell.

As a result, insulin promotes glucose uptake and glycogenesis, which is the conversion of glucose to glycogen. Glycogenesis is the process that takes place in the liver and skeletal muscles. When glycogen storage capacity is reached, insulin promotes glycolysis, which is the breakdown of glucose to pyruvate. It also stimulates lipogenesis, the synthesis of fatty acids and triglycerides in the liver and adipose tissue; and amino acid uptake and protein synthesis in skeletal muscles.

Finally, insulin activates Na+/K+- ATPase pumps and shifts potassium into intracellular space, thereby decreasing potassium levels in the blood. On the flip side, insulin inhibits glycogenolysis, which stands for the breakdown of glycogen; and gluconeogenesis, which is glucose production from lactic acids and noncarbohydrate molecules. Finally, insulin inhibits lipolysis, the breakdown of lipids; and proteolysis, the breakdown of proteins.


  1. "Katzung & Trevor's Pharmacology Examination and Board Review,12th Edition" McGraw-Hill Education / Medical (2018)
  2. "Rang and Dale's Pharmacology" Elsevier (2019)
  3. "Goodman and Gilman's The Pharmacological Basis of Therapeutics, 13th Edition" McGraw-Hill Education / Medical (2017)
  4. "Insulin lispro: a fast-acting insulin analog" Am Fam Physician (1998)
  5. "Rapid-Acting and Human Insulins: Hexamer Dissociation Kinetics upon Dilution of the Pharmaceutical Formulation" Pharmaceutical Research (2017)
  6. "Short-acting insulin analogues versus regular human insulin for adults with type 1 diabetes mellitus" Cochrane Database of Systematic Reviews (2016)

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