Provided is an insulin-producing cell inducer, an enhancer for glucose intake of muscles, and a therapeutic agent for diabetes or diabetes complications, wherein an active ingredient of those provided is an estrogenic compound such as estrogen and estradiol. With the present invention, functions of insulin-producing cells can be recovered since the insulin-producing cells are induced in pancreatic ducts, and blood glucose level can be immediately lowered since glucose in the blood can be effectively taken up by muscles； therefore, diabetes and diabetes complications can be prevented or treated.
