Insulin, synthesized by the beta cells of the islets of Langerhans, consists of 2 dissimilar polypeptide chains, A and B, which are linked by 2 disulfide bonds. The human insulin gene contains 3 exons; exon 2 encodes the signal peptide, the B chain, and part of the C peptide, while exon 3 encodes the remainder of the C peptide and the A chain. Insulin has a potent acute antiinflammatory effect, including a reduction in intranuclear NF-kappa-B, an increase in IKB, and decreases in the generation of reactive oxygen species. It causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen inside these tissues. And improved insulin-stimulated glucose uptake after endurance training results from hemodynamic adaptations as well as increased cellular protein content of individual insulin signaling components and molecules involved in glucose transport and metabolism.