insulinas

Insulins (insulinas) are a group of peptide hormones produced by the beta cells of the pancreatic islets of Langerhans. They play a central role in regulating blood glucose by stimulating glucose uptake in muscle and adipose tissue, inhibiting hepatic glucose production, and modulating lipid and protein metabolism. In diabetes mellitus, insufficient endogenous insulin or ineffective insulin signaling necessitates exogenous insulin therapy to achieve glycemic control.

Human insulin consists of two chains, A and B, linked by disulfide bonds. It is produced from larger precursors as preproinsulin and proinsulin, then processed to mature insulin and C-peptide. Therapeutic insulins are manufactured as human insulin or engineered analogs with altered pharmacokinetic properties to adjust onset and duration of action.

Therapeutic formulations vary by onset and duration: rapid-acting analogs such as lispro, aspart, and glulisine; short-acting regular insulin; intermediate-acting NPH; long-acting analogs such as glargine, detemir, and degludec; and fixed combinations. Administration is usually subcutaneous, with dosing tailored to meals, activity, and individual insulin sensitivity. Some patients use insulin pumps, while a fast-acting inhaled insulin is available in certain markets.

Pharmacokinetics differ among preparations, with peak activity ranging from about 30 minutes to several hours and durations from 8 to more than 24 hours. Blood glucose monitoring is essential to avoid hypoglycemia and hyperglycemia. Insulin therapy may require adjustments during illness, pregnancy, or changes in exercise and diet.

Insulin was first discovered in 1921 by Frederick Banting and Charles Best, with rapid clinical adoption following the purification of insulin. Since the 1980s, most therapeutic insulins are produced by recombinant DNA technology in bacteria or yeast. Animal-derived insulins were used historically but are now rare.

Storage and safety guidelines emphasize refrigeration for unopened vials and room-temperature storage after opening for a limited period. Insulins must be injected subcutaneously in appropriate sites to preserve absorption. Common adverse effects include hypoglycemia, weight gain, and lipodystrophy at injection sites; hypoglycemia risk may be influenced by concomitant medications and comorbidities.