Gelfand R A, Glickman M G, Jacob R, Sherwin R S, DeFronzo R A
Am J Physiol. 1986 Apr;250(4 Pt 1):E407-13. doi: 10.1152/ajpendo.1986.250.4.E407.
To compare the contributions of splanchnic and skeletal muscle tissues to the disposal of intravenously administered amino acids, regional amino acid exchange was measured across the splanchnic bed and leg in 11 normal volunteers. Postabsorptively, net release of amino acids by leg (largely alanine and glutamine) was complemented by the net splanchnic uptake of amino acids. Amino acid infusion via peripheral vein (0.2 g X kg-1 X h-1) caused a doubling of plasma insulin and glucagon levels and a threefold rise in blood amino acid concentrations. Both splanchnic and leg tissues showed significant uptake of infused amino acids. Splanchnic tissues accounted for approximately 70% of the total body amino acid nitrogen disposal; splanchnic uptake was greatest for the glucogenic amino acids but also included significant quantities of branched-chain amino acids. In contrast, leg amino acid uptake was dominated by the branched-chain amino acids. Based on the measured leg balance, body skeletal muscle was estimated to remove approximately 25-30% of the total infused amino acid load and approximately 65-70% of the infused branched-chain amino acids. Amino acid infusion significantly stimulated both the leg efflux and the splanchnic uptake of glutamine (not contained in the infusate). We conclude that when amino acids are infused peripherally in normal humans, splanchnic viscera (liver and gut) are the major sites of amino acid disposal.
为比较内脏组织和骨骼肌组织在静脉输注氨基酸代谢中的作用，对11名正常志愿者的内脏床和腿部的局部氨基酸交换情况进行了测定。在吸收后状态下，腿部氨基酸的净释放（主要是丙氨酸和谷氨酰胺）与内脏对氨基酸的净摄取相互补充。经外周静脉输注氨基酸（0.2 g·kg⁻¹·h⁻¹）使血浆胰岛素和胰高血糖素水平加倍，血液氨基酸浓度升高了两倍。内脏组织和腿部组织均显示出对输注氨基酸的显著摄取。内脏组织约占全身氨基酸氮代谢的70%；内脏对生糖氨基酸的摄取最多，但也包括大量的支链氨基酸。相比之下，腿部对氨基酸的摄取以支链氨基酸为主。根据测得的腿部平衡情况，估计全身骨骼肌摄取了约25% - 30%的输注氨基酸总量和约65% - 70%的输注支链氨基酸。氨基酸输注显著刺激了谷氨酰胺（输注液中不含）的腿部流出和内脏摄取。我们得出结论，在正常人体内经外周输注氨基酸时，内脏器官（肝脏和肠道）是氨基酸代谢的主要部位。
