Klein S, Young V R, Blackburn G L, Bistrian B R, Wolfe R R
Department of Internal Medicine, University of Texas Medical Branch, Galveston 77550.
J Am Coll Nutr. 1988 Feb;7(1):77-84. doi: 10.1080/07315724.1988.10720223.
Lipolytic rates were determined in normal-weight young adult (low body fat), normal-weight elderly (moderate body fat), and obese young adult (high body fat) subjects after an overnight (12-15 hr) and short-term (60-87 hr) fasting period. A simultaneous infusion of [1-13C] palmitate acid and [2H5]glycerol was used to measure the inflow of palmitate and glycerol into the bloodstream, and H2 18O dilution was used to measure body composition. The amount of body fat differed between the young adult (11 kg), elderly (23 kg) and obese (49 kg) subjects. Total lean body mass was similar in the normal-weight young adult (60 kg) and obese (63 kg) groups, but was lower in the elderly (46 kg). Lipolytic rates per unit of fat mass decreased in each group relative to the increase in the amount of body fat. Lipolytic rates, expressed as a function of lean body mass, however, were the same in all three groups. These results suggest that body composition contributes to the regulation of lipolysis during fasting. The decreased rate of lipolysis in subjects who have excess body fat may reflect the decreased need, per unit fat mass, for lipolysis to meet the energy requirements of the lean body mass.
在正常体重的年轻成年人（低体脂）、正常体重的老年人（中等体脂）和肥胖的年轻成年人（高体脂）受试者中，分别在禁食过夜（12 - 15小时）和短期禁食（60 - 87小时）后测定脂肪分解率。通过同时输注[1 - 13C]棕榈酸和[2H5]甘油来测量棕榈酸和甘油进入血液的流量，并使用H2 18O稀释法来测量身体成分。年轻成年人（11千克）、老年人（23千克）和肥胖者（49千克）的体脂量有所不同。正常体重的年轻成年人（60千克）和肥胖者（63千克）组的总体瘦体重相似，但老年人（46千克）的总体瘦体重较低。相对于体脂量的增加，每组每单位脂肪量的脂肪分解率均降低。然而，以瘦体重为函数表示的脂肪分解率在所有三组中是相同的。这些结果表明，身体成分在禁食期间有助于脂肪分解的调节。体脂过多的受试者脂肪分解率降低可能反映出每单位脂肪量对脂肪分解以满足瘦体重能量需求的需求减少。
