Insulin Insulin Insulin (from Latin "insula", island) is a peptide hormone produced by beta cells of the pancreatic islets; it is considered to be the main anabolic hormone of the body. It regulates the metabolism of carbohydrates, fats and protein by promoting the absorption of carbohydrates, especially glucose from the blood into liver, fat and skeletal muscle cells. In these tissues the absorbed glucose is converted into either glycogen via glycogenesis or fats (triglycerides) via lipogenesis, or, in the case of the liver, into both. Glucose production and secretion by the liver is strongly inhibited by high concentrations of insulin in
Insulin resistance (generally caused by insulin resistance), this down-regulation acts as a kind of positive feedback, increasing the need for insulin. Exercise reverses this process in muscle tissue, but if it is left unchecked, it may contribute to insulin resistance. Elevated blood levels of glucose—regardless of cause—lead to increased glycation of proteins with changes, only a few of which are understood in any detail, in protein function throughout the body. Insulin resistance often is found in people with visceral adiposity (i.e., a high degree of fatty tissue within the abdomen—as distinct from subcutaneous adiposity or fat between the skin and the muscle