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目的通过示踪剂动态观察蛋白质和氨基酸的代谢变化过程中在同位素丰度达到稳定的平台期时,不同的时间点血液中标记氨基酸的丰度与浓度的变化,以此反映不同时点蛋白质和氨基酸的氧化分解状况。方法选取20名健康成年男性为研究对象,分为2组,以7 d为一个实验周期,给予受试者日常膳食5 d后,第6天经静脉滴注给予稳定同位素13C标记的亮氨酸,持续3 h。在输液结束前的30 min内每隔15 min取一次血液样品,测定血样中亮氨酸的浓度与13C的丰度值,并比较各时点丰度及浓度的差异性。结果二组受试者3个时间点亮氨酸的浓度与13C丰度值之间的差异无统计学意义。结论在进食状态下持续给予受试者稳定同位素的过程中,不同时间点机体蛋白质和氨基酸的氧化分解处于一个相对稳定的状态,可以在此时期内确定一个同一的时间点来研究机体处于不同的蛋白质和氨基酸营养状态下的各项代谢动力学参数。
OBJECTIVE To observe the changes of the abundance and concentration of amino acids in blood at different time points when the isotope abundance reaches a stable plateau during the metabolic changes of proteins and amino acids by means of tracer. Amino acid oxidation and decomposition of the situation. Methods Twenty healthy adult male subjects were selected and divided into two groups. The experimental group was given an experimental period of 7 days, and the subjects were given daily diet for 5 days. The stable isotope 13C-labeled leucine For 3 h. Blood samples were taken every 15 min before the end of infusion to determine the leucine concentration and 13C abundance in the blood samples, and the differences in abundance and concentration at each time point were compared. Results There was no significant difference between the concentrations of leucine and 13C in the three time points of the two groups. Conclusion During the continuous administration of stable isotopes to the subjects under the condition of feeding, the oxidative decomposition of protein and amino acids in the body at different time points is in a relatively stable state. During this period, a same time point can be determined to study whether the body is in different Various pharmacokinetic parameters of protein and amino acid nutrition.