WATER HYDROGEN INCORPORATION INTO BODY-FAT IN PIGS - EFFECT ON DOUBLE TRIPLE-LABELED WATER METHOD
WATER HYDROGEN INCORPORATION INTO BODY-FAT IN PIGS - EFFECT ON DOUBLE TRIPLE-LABELED WATER METHOD
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DOI：
10.1152/ajpregu.1991.260.3.r627
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发表时间：
1991-03-01
影响因子：
--
通讯作者：
WONG, WW
中科院分区：
文献类型：
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作者：
HAGGARTY, P;MCGAW, BA;WONG, WW
双标记水（DLW）和三标记水（TLW）测量水通量（r(H2)O）、CO2产量（r(CO2)）和分馏失水(X)的基本假设是，体内水分的H只以水的形式离开体内。其他产品中任何同位素的损失都会给这些技术带来误差。体脂是水h的最大潜在储存库，研究了8头用(H2O)-H-2标记21天的猪体内H-2在胴体脂肪酸中的封存情况。在呼吸室中同时测量r(CO2)，以便准确评估H-2固存对估计r（CO2）的影响。饲粮脂肪含量（1.63%）、采食水平和成熟期的设计都是为了提供尽可能广泛的封存效果。4只动物被限制在其估计的维持需求范围内，4只动物被允许自由饲喂，体重增加范围为100至650克/天。这反映在r(H2O)（限制组+0.42%，速生组+2.52%）和r(CO2)（分别为-1.30和-7.59%）的估计误差上。使用TLW计算X时，限制组误差为+0.03个单位，速生动物误差为+0.20个单位。X上+0.2的误差传播到r（CO2）的低估约为4%，并且由于这与DLW上的误差是相加的，因此使用TLW时r（CO2）的最终误差将约为-12%。将误差外推到零增重表明，在体重稳定的动物中，胴体脂肪酸的周转很少，r（H2O）、r（CO2）或X的误差也不显著。然而，在快速生长过程中，r（H2O）、r（CO2）和X的同位素推导参数误差可能很大。因此，在解释来自DLW和TLW研究的同位素通量数据时，当有组织生长或输出时，特别是当这涉及脂肪酸合成时，考虑水H封存的可能程度是谨慎的。
A basic assumption of the doubly labeled water (DLW) and triply labeled water (TLW) methods for measuring water flux (r(H2)O), CO2 production (r(CO2)), and fractionated water loss (X) is that the H of body water only leaves the body as water. Any loss of isotopes in other products will introduce an error into these techniques. The body fat represents the largest potential sink for water H. H-2 sequestration into the carcass fatty acids was investigated in eight pigs labeled with (H2O)-H-2 for 21 days. r(CO2) was measured simultaneously in respiration chambers to allow an accurate assessment of the effect of H-2 sequestration on the estimated r(CO2). The fat content of the diet (1.63%), level of intake, and stage of maturity were all designed to give the widest possible range of sequestration effects. Four animals were restricted to their estimated maintenance requirement and four were allowed to feed ad libitum giving a range of weight gain from 100 to 650 g/day. This was reflected in the estimated error on r(H2O) (+0.42% in the restricted group and +2.52% in the fast-growing animals) and on r(CO2) (-1.30 and -7.59%, respectively). The error on the calculation of X using TLW was +0.03 units in the restricted group and +0.20 units in the fast-growing animals. The error of +0.2 on X propagates through to an underestimate of r(CO2) of approximately 4%, and since this is additive with the error on DLW the ultimate error on r(CO2) using TLW would be approximately -12%. Extrapolation of the errors to zero weight gain indicated that there would be very little turnover of the carcass fatty acids and no significant error on either r(H2O), r(CO2), or X in weight-stable animals. However, the errors on the isotopically derived parameters of r(H2O), r(CO2), and X can be substantial during rapid growth. It would therefore be prudent to consider the likely extent of water H sequestration when interpreting isotope flux data from DLW and TLW studies when there is growth or export of tissue, particularly when this involves fatty acid synthesis.