Dumas J-F, Bielicki G, Renou J-P, Roussel D, Ducluzeau P-H, Malthièry Y, Simard G, Ritz P
Inserm EMI-U 00.18, Laboratoire de Biochimie et de Biologie Moléculaire, CHU, 4 rue Larrey, 49033 Angers Cedex, France.
Diabetologia. 2005 Feb;48(2):328-35. doi: 10.1007/s00125-004-1631-0. Epub 2005 Jan 8.
AIMS/HYPOTHESIS: Glucocorticoid treatments are associated with increased whole-body oxygen consumption. We hypothesised that an impairment of muscle energy metabolism can participate in this increased energy expenditure.
To investigate this possibility, we have studied muscle energetics of dexamethasone-treated rats (1.5 mg kg(-1) day(-1) for 6 days), in vivo by (31)P NMR spectroscopy. Results were compared with control and pair-fed (PF) rats before and after overnight fasting.
Dexamethasone treatment resulted in decreased phosphocreatine (PCr) concentration and PCr:ATP ratio, increased ADP concentration and higher PCr to gamma-ATP flux but no change in beta-ATP to beta-ADP flux in gastrocnemius muscle. Neither 4 days of food restriction (PF rats) nor 24 h fasting affected high-energy phosphate metabolism. In dexamethasone-treated rats, there was an increase in plasma insulin and non-esterified fatty acid concentration.
CONCLUSIONS/INTERPRETATION: We conclude that dexamethasone treatment altered resting in vivo skeletal muscle energy metabolism, by decreasing oxidative phosphorylation, producing ATP at the expense of PCr.
目的/假设：糖皮质激素治疗与全身氧消耗增加有关。我们推测肌肉能量代谢受损可能参与了这种能量消耗的增加。
为了研究这种可能性，我们通过（31）P核磁共振波谱法对接受地塞米松治疗的大鼠（1.5毫克/千克/天，持续6天）的肌肉能量学进行了体内研究。将结果与对照组和配对喂养（PF）大鼠在禁食过夜前后进行比较。
地塞米松治疗导致腓肠肌中磷酸肌酸（PCr）浓度和PCr:ATP比值降低，ADP浓度升高，PCr至γ-ATP通量增加，但β-ATP至β-ADP通量无变化。4天的食物限制（PF大鼠）和24小时禁食均未影响高能磷酸代谢。在地塞米松治疗的大鼠中，血浆胰岛素和非酯化脂肪酸浓度增加。
结论/解读：我们得出结论，地塞米松治疗改变了静息状态下的体内骨骼肌能量代谢，通过降低氧化磷酸化，以消耗PCr为代价产生ATP。
