title: Athletes with IDDM exhibit impaired metabolic control and increased lipid utilization with no increase in insulin sensitivity.
abstract: Physical exercise is traditionally recommended to diabetic patients as part of their treatment. Although healthy athletes exhibit enhanced skeletal muscle insulin sensitivity, the metabolic effects of vigorous training in patients with insulin-dependent diabetes mellitus (IDDM) are not known. This study was designed to examine the effects of competitive sports on fuel homeostasis and insulin sensitivity in athletes with IDDM. We studied 11 athletes and 12 matched sedentary men with IDDM. In each subject, we measured glycemic control, insulin-stimulated glucose uptake in the whole body and forearm, rates of glucose and lipid oxidation, and muscle glycogen, glycogen synthase, and glucose transport protein (GLUT4) concentrations. The athletes had higher VO2max (52 +/- 1 vs. 42 +/- 1 ml.kg-1.min-1, P < 0.001) and HbA1c levels (8.4 +/- 0.4 vs. 7.2 +/- 0.2%, P < 0.05) than sedentary patients, but took smaller insulin doses (41 +/- 3 vs. 53 +/- 3 U/day, P < 0.05). The insulin-stimulated rates of whole-body and forearm glucose uptake and glucose oxidation were similar in the two groups, whereas both energy expenditure and lipid oxidation were increased in the athletes. Lipid oxidation correlated inversely with glycogen synthase activity. The mean glucose arterialized venous blood-deep venous blood (A-V) difference during the insulin infusion (60-240 min) correlated with the whole-body glucose disposal throughout the insulin infusion (after 60 min, r > 0.73, P < 0.001 for all 30-min periods). This association is accounted for by the relationship between glucose A-V difference and nonoxidative glucose disposal. Muscle glycogen and GLUT4 protein contents were not different in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Second Department of Medicine, Helsinki University Hospital, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Ebeling
authors.forename: J A
authors.initials: JA
authors.lastname: Tuominen
authors.forename: R
authors.initials: R
authors.lastname: Bourey
authors.forename: L
authors.initials: L
authors.lastname: Koranyi
authors.forename: V A
authors.initials: VA
authors.lastname: Koivisto
mesh_terms: D000328:Adult; D001823:Body Composition; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D015870:Gene Expression; D005947:Glucose / Q000378:metabolism; D051275:Glucose Transporter Type 4; D006006:Glycogen Synthase / Q000235:genetics / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D007328:Insulin / Q000378:metabolism; D050356:Lipid Metabolism; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism; D009124:Muscle Proteins; D009132:Muscles / Q000378:metabolism; D005082:Physical Exertion; D010809:Physical Fitness; D012333:RNA, Messenger / Q000235:genetics; D012039:Regional Blood Flow
chemical_list: D005230:Fatty Acids, Nonesterified; D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; C495692:SLC2A4 protein, human; D006006:Glycogen Synthase; D005947:Glucose