Abstract | BACKGROUND: METHODS AND FINDINGS: We measured G-6-P, ATP synthetic flux (i.e., synthesis) and lipid contents of skeletal muscle with (31)P/(1)H magnetic resonance spectroscopy in ten patients with T2DM and in two control groups: ten sex-, age-, and body mass-matched elderly people; and 11 younger healthy individuals. Although insulin sensitivity was lower in patients with T2DM, muscle lipid contents were comparable and hyperinsulinemia increased G-6-P by 50% (95% confidence interval [CI] 39%-99%) in all groups. Patients with diabetes had 27% lower fasting ATP synthetic flux compared to younger controls (p = 0.031). Insulin stimulation increased ATP synthetic flux only in controls (younger: 26%, 95% CI 13%-42%; older: 11%, 95% CI 2%-25%), but failed to increase even during hyperglycemic hyperinsulinemia in patients with T2DM. Fasting free fatty acids and waist-to-hip ratios explained 44% of basal ATP synthetic flux. Insulin sensitivity explained 30% of insulin-stimulated ATP synthetic flux. CONCLUSIONS: Patients with well-controlled T2DM feature slightly lower flux through muscle ATP synthesis, which occurs independently of glucose transport /phosphorylation and lipid deposition but is determined by lipid availability and insulin sensitivity. Furthermore, the reduction in insulin-stimulated glucose disposal despite normal glucose transport/phosphorylation suggests further abnormalities mainly in glycogen synthesis in these patients.
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Authors | Julia Szendroedi, Albrecht I Schmid, Marek Chmelik, Christian Toth, Attila Brehm, Martin Krssak, Peter Nowotny, Michael Wolzt, Werner Waldhausl, Michael Roden |
Journal | PLoS medicine
(PLoS Med)
Vol. 4
Issue 5
Pg. e154
(May 2007)
ISSN: 1549-1676 [Electronic] United States |
PMID | 17472434
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Blood Glucose
- Fatty Acids, Nonesterified
- Glucose-6-Phosphate
- Adenosine Triphosphate
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Topics |
- Adenosine Triphosphate
(biosynthesis)
- Adipose Tissue
(metabolism, physiology)
- Adult
- Aged
- Blood Glucose
(metabolism)
- Diabetes Mellitus, Type 2
(metabolism)
- Fatty Acids, Nonesterified
(metabolism)
- Female
- Glucose Clamp Technique
- Glucose-6-Phosphate
(blood)
- Humans
- Insulin Resistance
(physiology)
- Magnetic Resonance Spectroscopy
- Male
- Middle Aged
- Mitochondria, Muscle
(metabolism)
- Obesity
(metabolism, physiopathology)
- Phosphorylation
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