Exercise training attenuated the PKB and GSK-3 dephosphorylation in the myocardium of ZDF rats.
Cardiac dysfunction is a severe secondary effect of Type 2 diabetes. Recruitment of the protein kinase B/glycogen synthase kinase-3 pathway represents an integral event in glucose homeostasis, albeit its regulation in the diabetic heart remains undefined. Thus the following study tested the hypothesis that the regulation of protein kinase B/glycogen synthase kinase-3 was altered in the myocardium of the Zucker diabetic fatty rat. Second, exercise has been shown to improve glucose homeostasis, and, in this regard, the effect of swimming training on the regulation of protein kinase B/glycogen synthase kinase-3 in the diabetic rat heart was examined. In the sedentary Zucker diabetic fatty rats, glucose levels were elevated, and cardiac glycogen content increased, compared with wild type. A 13-wk swimming regimen significantly reduced plasma glucose levels and cardiac glycogen content and partially normalized protein kinase B-serine473, protein kinase B-threonine308, and glycogen synthase kinase-3alpha phosphorylation in Zucker diabetic fatty rats. In conclusion, hyperglycemia and increased cardiac glycogen content in the Zucker diabetic fatty rats were associated with dysregulation of protein kinase B/glycogen synthase kinase-3 phosphorylation. These anomalies in the Zucker diabetic fatty rat were partially normalized with swimming. These data support the premise that exercise training may protect the heart against the deleterious consequences of diabetes.
Lajoie
Claude
C
Department of Kinesiology, University of Montreal, Montreal, Québec H3C 3J7, Canada.
Calderone
Angelino
A
Trudeau
François
F
Lavoie
Nathalie
N
Massicotte
Guy
G
Gagnon
Sylvain
S
Béliveau
Louise
L
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003920:Diabetes Mellitus / Q000097:blood / Q000201:enzymology* / Q000378:metabolism; D006003:Glycogen / Q000097:blood; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D050884:HSP72 Heat-Shock Proteins; D006352:Heart Ventricles; D006360:Heat-Shock Proteins / Q000378:metabolism; D006943:Hyperglycemia / Q000097:blood; D007328:Insulin / Q000097:blood; D008297:Male; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism; D009206:Myocardium / Q000201:enzymology*; D025221:Phosphofructokinases / Q000378:metabolism; D010766:Phosphorylation; D010805:Physical Conditioning, Animal; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D011924:Rats, Zucker; D013550:Swimming
D001786:Blood Glucose; D050884:HSP72 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D007328:Insulin; D011518:Proto-Oncogene Proteins; D006003:Glycogen; D025221:Phosphofructokinases; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D038362:Glycogen Synthase Kinase 3