inzulin

Inzulin, commonly referred to as insulin, is a peptide hormone produced by the beta cells of the pancreatic islets. It is a central regulator of carbohydrate and fat metabolism, lowering blood glucose by promoting glucose uptake into liver, skeletal muscle, and adipose tissue and by inhibiting hepatic glucose production. It also promotes protein synthesis and fat storage.

Physiology: Endogenous inzulin is synthesized as preproinsulin and processed to proinsulin and mature insulin, stored in secretory granules and released in response to rising blood glucose, amino acids, and incretin signals. Release is pulsatile and subject to autonomic regulation.

Pharmacology and forms: Exogenous insulin preparations vary by onset and duration. Rapid-acting analogs (lispro, aspart, glulisine) begin within 10–20 minutes and last 3–5 hours. Short-acting regular insulin starts about 30–60 minutes and lasts 6–8 hours. Intermediate-acting NPH lasts roughly 12–16 hours. Long-acting analogs (glargine, detemir, degludec) provide baseline coverage for 24 hours or longer. Administration is usually subcutaneous; insulin pumps deliver continuous infusion; inhaled insulin exists but is less common. Storage: refrigeration before opening; room temperature for a limited time after opening.

Clinical use: Inzulin is essential for the management of type 1 diabetes and is used in many people with type 2 diabetes when other therapies are insufficient. It is also used during pregnancy when needed and, in some settings, to treat hyperkalemia by shifting potassium into cells.

Safety: The main risk is hypoglycemia; other risks include weight gain and rarely injection-site lipodystrophy or allergic reactions.

History: Insulin was discovered in 1921 by Banting and Best, transforming the treatment of diabetes.