Lysine and protein metabolism in young women. Subdivision based on the novel use of multiple stable isotopic labels.
Lysine and protein metabolism in young women. Subdivision based on the novel use of multiple stable isotopic labels.
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年轻女性的赖氨酸和蛋白质代谢。
DOI：
10.1172/jci112437
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Klein,PD
中科院分区：
文献类型：
--
作者：
Irving,CS;Thomas,MR;Malphus,EW;Marks,L;Wong,WW;Boutton,TW;Klein,PD
在禁食的成年女性志愿者中进行赖氨酸动力学的多示踪剂稳定同位素研究，以确定是否可以从血浆和呼吸数据构建将蛋白质合成和分解分成至少两种类型的组织组分的多房室模型。5名维持配方饲料的女性受试者在餐后4小时接受L-[13 C1]赖氨酸（27 mumol/kg）静脉推注和L-[15 N2]赖氨酸（27 mumol/kg）口服推注。采集血浆和呼吸样本6 h。隔日，受试者接受NaH 13 CO 3（10 mumol/kg）静脉推注，并采集6 h呼吸样本。血浆示踪剂赖氨酸水平通过气相色谱-质谱同位素比值法测定，呼吸13 CO2水平通过质谱气体同位素比值法测定。示踪剂数据可以拟合到一个乳头状多房室模型，该模型由赖氨酸中央室和缓慢和快速交换外周室分别含有37，38和324 μ mol/kg。在快速交换室中，赖氨酸氧化、掺入蛋白质和蛋白质分解释放的速率分别为21、35和56 mmol/kg/h，而在慢速交换室中，蛋白质合成和分解的速率均为53 mmol/kg/min。这些值对应于106 mmol/kg/h的全身赖氨酸通量。的动力学参数是在很好的协议与报告的值通过恒定输注方法获得。测量结果表明，这将是可能的，以检测氨基酸池的大小和蛋白质的合成和分解与动员的蛋白质存储从血浆和呼吸测量在多示踪剂稳定同位素实验的变化。
A multitracer stable isotope study of lysine kinetics was carried out in fasted adult female volunteers to determine whether a multicompartmental model that partitions protein synthesis and breakdown into at least two types of tissue components can be constructed from plasma and breath data. Five female subjects, maintained on formula diets, received L-[13C1]lysine (27 mumol/kg) as an i.v. bolus and L-[15N2]lysine (27 mumol/kg) as an oral bolus 4 h postprandially. Plasma and breath samples were collected for 6 h. On an alternate day, subjects received NaH13CO3 (10 mumol/kg) as an i.v. bolus and breath samples were collected for 6 h. Plasma tracer lysine levels were determined by gas chromatography-mass spectrometry isotope ratiometry, and breath 13CO2 levels were measured by mass spectrometric gas isotope ratiometry. The tracer data could be fitted to a mammillary multicompartmental model that consisted of a lysine central compartment and slow- and fast-exchanging peripheral compartments containing 37, 38, and 324 mumol/kg, respectively. The rates of lysine oxidation, incorporation into protein, and release by protein breakdown were 21, 35, and 56 mmol/kg/h, respectively, in the fast-exchanging compartment, whereas the rates of protein synthesis and breakdown in the slow compartment were both 53 mmol/kg/min. These values corresponded to a whole-body lysine flux of 106 mmol/kg/h. The kinetic parameters were in excellent agreement with reported values obtained by constant-infusion methods. The measurements indicated that it will be possible to detect changes in amino acid pool sizes and protein synthesis and breakdown associated with the mobilization of protein stores from plasma and breath measurements in multitracer stable isotope experiments.