| Noun | 1. | insulin - hormone secreted by the isles of Langerhans in the pancreas; regulates storage of glycogen in the liver and accelerates oxidation of sugar in cellsHumulin, recombinant human insulin - a form of insulin (trade name Humulin) made from recombinant DNA that is identical to human insulin; used to treat diabetics who are allergic to preparations made from beef or pork insulin | |