Aminoacyl-tRNA enrichment after a flood of labeled phenylalanine: insulin effect on muscle protein synthesis
Aminoacyl-tRNA enrichment after a flood of labeled phenylalanine: insulin effect on muscle protein synthesis
复制标题
DOI：
10.1152/ajpendo.00215.2001
复制
发表时间：
2002-05-01
影响因子：
5.1
通讯作者：
McNurlan, MA
中科院分区：
文献类型：
--
作者：
Caso, G;Ford, GC;McNurlan, MA
用L-[H-2（5）]苯丙氨酸（70 mg/kg）灌流测定的狗肌肉蛋白质合成，通过输注胰岛素和氨基酸显著刺激。当从苯丙氨酰-tRNA（61 ± 10%，P < 0.001）、血浆苯丙氨酸（61 ± 10%，P <0.001）或组织液苯丙氨酸（54 ± 10%，P <0.001）的富集计算时，肌肉蛋白质合成的刺激是相似的。在基础状态下和输注含氨基酸胰岛素期间，测定血浆、组织液和苯丙氨酰-tRNA在整个泛血期L-[H-2（5）]苯丙氨酸富集变化的时间进程。血浆游离苯丙氨酸和苯丙氨酰-tRNA的富集在20和45分钟之间均衡，尽管苯丙氨酰-tRNA的富集在早期时间点较低。与洪水的方法和血浆苯丙氨酸富集计算得到的肌肉蛋白质的合成率是可比的计算从苯丙氨酰-tRNA，也与以前获得的苯丙氨酸与苯丙氨酰-tRNA作为前体的连续输液。这项研究证实，与标记的苯丙氨酸，富集氨酰-tRNA，蛋白质合成的真正的前体池，可以从更容易采样的血浆苯丙氨酸进行评估推注。
Muscle protein synthesis in dogs measured by flooding with L-[H-2(5)] phenylalanine (70 mg/kg) was significantly stimulated by infusion of insulin with amino acids. The stimulation of muscle protein synthesis was similar when calculated from the enrichment of phenylalanyl-tRNA (61 +/- 10%, P < 0.001), plasma phenylalanine (61 ± 10%, P < 0.001), or tissue fluid phenylalanine (54 +/- 10%, P < 0.001). The time course for changes in enrichment of L-[H-2(5)] phenylalanine throughout the flooding period was determined for plasma, tissue fluid, and phenylalanyl-tRNA in the basal state and during the infusion of insulin with amino acids. Enrichments of plasma free phenylalanine and phenylalanyl-tRNA were equalized between 20 and 45 min, although the enrichment of phenylalanyl-tRNA was lower at early time points. Rates of muscle protein synthesis obtained with the flooding method and calculated from plasma phenylalanine enrichment were comparable to those calculated from phenylalanyl-tRNA and also to those obtained previously with a continuous infusion of phenylalanine with phenylalanyl-tRNA as precursor. This study confirms that, with a bolus injection of labeled phenylalanine, the enrichment of aminoacyl-tRNA, the true precursor pool for protein synthesis, can be assessed from more readily sampled plasma phenylalanine.