title: Morphological assessment of pancreatic islet hormone content following aerobic exercise training in rats with poorly controlled Type 1 diabetes mellitus.
abstract: Regular exercise has been shown to improve many complications of Type 1 diabetes mellitus (T1DM) including enhanced glucose tolerance and increased cardiac function. While exercise training has been shown to increase insulin content in pancreatic islets of rats with T1DM, experimental models were severely hyperglycemic and not undergoing insulin treatment. Further, research to date has yet to determine how exercise training alters glucagon content in pancreatic islets. The purpose of the present investigation was to determine the impact of a 10-week aerobic training program on pancreatic islet composition in insulin-treated rats with T1DM. Second, it was determined whether the acute, exercise-mediated reduction in blood glucose experienced in rats with T1DM would become larger in magnitude following aerobic exercise training. Diabetes was induced in male Sprague-Dawley rats by multiple low dose injections of streptozotocin (20mg/kg i.p.) and moderate intensity aerobic exercise training was performed on a motorized treadmill for one hour per day for a total of 10 weeks. Rats with T1DM demonstrated significantly less islet insulin, and significantly more islet glucagon hormone content compared with non-T1DM rats, which did not significantly change following aerobic training. The reduction in blood glucose in response to a single exercise bout was similar across 10 weeks of training. Results also support the view that different subpopulations of islets exist, as small islets (<50 μm diameter) had significantly more insulin and glucagon in rats with and without T1DM.
authors.affiliation: a School of Kinesiology; Faculty of Health Sciences; University of Western Ontario; London, ON Canada.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: McDonald
authors.forename: Michael R
authors.initials: MR
authors.lastname: Murray
authors.forename: Katharine E
authors.initials: KE
authors.lastname: Hall
authors.forename: Earl G
authors.initials: EG
authors.lastname: Noble
authors.forename: C W James
authors.initials: CW
authors.lastname: Melling
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000097:blood* / Q000188:drug therapy; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000188:drug therapy; D005934:Glucagon / Q000378:metabolism*; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D007328:Insulin / Q000378:metabolism* / Q000627:therapeutic use; D007515:Islets of Langerhans / Q000378:metabolism* / Q000473:pathology; D008297:Male; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011972:Receptor, Insulin / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D051275:Glucose Transporter Type 4; D007328:Insulin; D005934:Glucagon; D011972:Receptor, Insulin
keywords: glucagon; hypoglycemia; insulin; moderate hyperglycemia; pancreatic islet; streptozotocin