title: Chronic exercise enhances insulin secretion ability of pancreatic islets without change in insulin content in non-diabetic rats.
abstract: We evaluated the effect of chronic exercise on insulin secretion in response to high-glucose by using a perifusion method with isolated pancreatic islets from normal rats. Male Wistar rats were assigned to one of two groups: a sedentary group and a trained group. Running exercise was carried out on a treadmill for one hour per day, five days per week, for six, nine, or 12 weeks. The chronic exercise significantly enhanced the insulin secretion ability of pancreatic islets in response to the high-glucose stimulation upon nine and 12 weeks of exercise. The insulin content in the pancreas and the weight of the pancreas did not change upon nine weeks of exercise. Potassium-stimulated insulin secretion was also increased in the islets isolated from rats that trained for nine weeks compared with that in sedentary rats, suggesting that insulin secretion events downstream of membrane depolarization are involved in targets of the exercise effect. These findings suggest that chronic exercise could be a useful strategy not only for the maintenance of peripheral insulin sensitivity but also for the promotion of islet function to secrete insulin in non-diabetics.
authors.affiliation: Department of Health Promotion Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Miho
authors.initials: M
authors.lastname: Tsuchiya
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Manabe
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Yamada
authors.forename: Yasuro
authors.initials: Y
authors.lastname: Furuichi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hosaka
authors.forename: Nobuharu L
authors.initials: NL
authors.lastname: Fujii
mesh_terms: D000818:Animals; D005080:Exercise Test; D005947:Glucose / Q000008:administration & dosage; D007328:Insulin / Q000008:administration & dosage / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D010805:Physical Conditioning, Animal; D011188:Potassium / Q000008:administration & dosage; D051381:Rats; D017208:Rats, Wistar; D057185:Sedentary Behavior
chemical_list: D007328:Insulin; D005947:Glucose; D011188:Potassium