Raben A, Mygind E, Astrup A
Research Department of Human Nutrition, Center for Food Research, The Royal Veterinary and Agricultural University, DK-1958 Frederiksberg, Denmark.
Am J Physiol. 1998 Sep;275(3):E487-94. doi: 10.1152/ajpendo.1998.275.3.E487.
Muscle fiber morphology and activities of four key enzymes, as well as energy metabolism, were determined in nine normal-weight postobese women and nine matched control subjects. No differences in fiber type composition, but a smaller mean fiber area and area of fiber types I and IIb, were found in postobese compared with control subjects (P < 0.05). The activities of beta-hydroxyacyl-CoA dehydrogenase (HADH) and citrate synthase (CS) were 20% lower in postobese than in control subjects (P < 0.05). However, the activities of lactate dehydrogenase and lipoprotein lipase were not significantly different between postobese and control subjects. Basal metabolic rate and respiratory exchange ratio were also similar, but maximal oxygen uptake (VO2 max) tended to be lower in postobese than in control subjects (P = 0.06). When adjustments were made for differences in VO2 max, HADH and CS were not different between postobese and control subjects. In conclusion, these data suggest that smaller fiber areas and lower enzyme activities, i.e., markers of aerobic capacity of skeletal muscle, but not fiber composition, may be factors predisposing to obesity.
对9名体重正常的肥胖后女性和9名匹配的对照受试者的肌纤维形态、四种关键酶的活性以及能量代谢进行了测定。与对照受试者相比，肥胖后受试者的纤维类型组成没有差异，但平均纤维面积以及I型和IIb型纤维面积较小（P < 0.05）。肥胖后受试者的β-羟酰基辅酶A脱氢酶（HADH）和柠檬酸合酶（CS）活性比对照受试者低20%（P < 0.05）。然而，肥胖后受试者与对照受试者之间乳酸脱氢酶和脂蛋白脂肪酶的活性没有显著差异。基础代谢率和呼吸交换率也相似，但肥胖后受试者的最大摄氧量（VO2 max）往往低于对照受试者（P = 0.06）。当对VO2 max的差异进行校正后，肥胖后受试者与对照受试者之间的HADH和CS没有差异。总之，这些数据表明，较小的纤维面积和较低的酶活性，即骨骼肌有氧能力的标志物，而非纤维组成，可能是导致肥胖的因素。
