title: The glucoregulatory response to high-intensity aerobic exercise following training in rats with insulin-treated type 1 diabetes mellitus.
abstract: An acute bout of exercise elicits a rapid, potentially deleterious, reduction in blood glucose in patients with type 1 diabetes mellitus (T1DM). In the current study, we examined whether a 10-week aerobic training program could alleviate the rapid exercise-associated reduction in blood glucose through changes in the glucoregulatory hormonal response or increased hepatic glycogen storage in an insulin-treated rat model of T1DM. Thirty-two male Sprague-Dawley rats were divided evenly into 4 groups: non-T1DM sedentary (C) (n = 8), non-T1DM exercised (CX) (n = 8), T1DM sedentary (D) (n = 8), and T1DM exercised (DX) (n = 8). Exercise training consisted of treadmill running for 5 days/week (1 h, 27 m/min, 6% grade) for 10 weeks. T1DM was induced by multiple streptozotocin injections (20 mg/kg) followed by implantation of subcutaneous insulin pellets. At week 1, an acute exercise bout led to a significant reduction in blood glucose in DX (p < 0.05), whereas CX exhibited an increase in blood glucose (p < 0.05). During acute exercise, serum epinephrine was increased in both DX and CX (p < 0.05), whereas serum glucagon was increased during recovery only in CX (p < 0.01). Following aerobic training in DX, the exercise-mediated reduction in blood glucose remained; however, serum glucagon increased to the same extent as in CX (p < 0.05). DX exhibited significantly less hepatic glycogen (p < 0.001) despite elevations in glycogenic proteins in the liver (p < 0.05). Elevated serum epinephrine and decreased hepatic adrenergic receptor expression were also evident in DX (p < 0.05). In summary, despite aerobic training in DX, abrupt blood glucose reductions and hepatic glycogen deficiencies were evident. These data suggest that sympathetic overactivity may contribute to deficiencies in hepatic glycogen storage.
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.affiliation: a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Murray
authors.affiliation: a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada.
authors.forename: Kenneth N
authors.initials: KN
authors.lastname: Grise
authors.affiliation: a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada.
authors.forename: T Dylan
authors.initials: TD
authors.lastname: Olver
authors.affiliation: a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada.
authors.forename: Adwitia
authors.initials: A
authors.lastname: Dey
authors.affiliation: a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada.|b Lawson Health Research Institute, University of Western Ontario, London, ON, Canada.
authors.forename: J Kevin
authors.initials: JK
authors.lastname: Shoemaker
authors.affiliation: a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada.|b Lawson Health Research Institute, University of Western Ontario, London, ON, Canada.
authors.forename: Earl G
authors.initials: EG
authors.lastname: Noble
authors.affiliation: a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada.|c School of Health Studies, Faculty of Health Sciences, University of Western Ontario, 3M Centre, Room 2213, London, ON, N6A 5B9 Canada.
authors.forename: C W James
authors.initials: CW
authors.lastname: Melling
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy*; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy*; D004837:Epinephrine / Q000097:blood; D005934:Glucagon / Q000097:blood; D006003:Glycogen / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D010805:Physical Conditioning, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D011941:Receptors, Adrenergic / Q000235:genetics / Q000378:metabolism; D057185:Sedentary Behavior
chemical_list: D001786:Blood Glucose; D007328:Insulin; D011941:Receptors, Adrenergic; D006003:Glycogen; D005934:Glucagon; D004837:Epinephrine
keywords: epinephrine; glucagon; glycogène hépatique; hepatic glycogen; hypoglycemia; hypoglycémie; insulin; insuline; épinéphrine