CONTRIBUTION OF LIVER AND SKELETAL-MUSCLE TO ALANINE AND LACTATE METABOLISM IN HUMANS
CONTRIBUTION OF LIVER AND SKELETAL-MUSCLE TO ALANINE AND LACTATE METABOLISM IN HUMANS
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DOI：
10.1152/ajpendo.1990.259.5.e677
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发表时间：
1990-11-01
影响因子：
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通讯作者：
GERICH, JE
中科院分区：
文献类型：
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作者：
CONSOLI, A;NURJHAN, N;GERICH, JE
为了定量吸收后人体中丙氨酸和乳酸盐的生成，并检验肌肉是这些前体的主要来源的假设，我们向正常志愿者输注[3- 14 C]乳酸盐、[3- 13 C]丙氨酸和[6- 3 H]葡萄糖，并计算丙氨酸和乳酸盐掺入三羧酸循环碳交换校正的血浆葡萄糖中，这些底物的全身表现，以及它们的前臂部分提取、摄取和释放。前臂丙氨酸和乳酸分数提取平均为37 ± 10%。3和27 .+-。2%;肌肉丙氨酸释放（2.94 ±. 0.27μ mol·cntdot. kg体重min-1）占70%的系统外观（4.18 ±. 0.31μ mol·cntdot. kg体重min-1）;肌肉乳酸盐释放（5.51 ± 0.001）; 0.42μ mol·cntdot. kg体重min-1）占40%的系统外观（12.66 ±. 0.77μ mol·cntdot. kg体重min-1）;肌肉丙氨酸和乳酸盐摄取（1.60 ± 0.001）。0.7和3.29 .+-。0.36μ mol·cntdot. kg体重min-1，分别）占. apprx. 30%，而丙氨酸和乳酸结合到血浆葡萄糖中（1.83 ± 0.30%）。0.20和4.24 .+-。0.44μ mol·cntdot. body wt-1.cntdot. min-1），分别计算。它们从血浆中消失的一半。因此，我们得出结论，肌肉是血浆丙氨酸和乳酸在吸收后的人的主要来源，并从肌肉中释放的调节因子，从而可能对肝再生产生重要影响。
To quantitate alanine and lactate gluconeogenesis in postabsorptive humans and to test the hypothesis that muscle is the principal source of these precursors, we infused normal volunteers with [3-14C]lactate, [3-13C]alanine, and [6-3H]glucose and calculated alanine and lactate incorporation into plasma glucose corrected for tricarboxylic acid cycle carbon exchange, the systemic appearance of these substrates, and their forearm fractional extraction, uptake, and release. Forearm alanine and lactate fractional extraction averaged 37 .+-. 3 and 27 .+-. 2%, respectively; muscle alanine release (2.94 .+-. 0.27 .mu.mol .cntdot. kg body wt-1 .cntdot. min-1) accounted for .apprx. 70% of its systemic appearance (4.18 .+-. 0.31 .mu.mol .cntdot. kg body wt-1 .cntdot. min-1); muscle lactate release (5.51 .+-. 0.42 .mu.mol .cntdot. kg body wt-1 .cntdot. min-1) accounted for .apprx. 40% of its systemic appearance (12.66 .+-. 0.77 .mu.mol .cntdot. kg body wt-1 .cntdot. min-1); muscle alanine and lactate uptake (1.60 .+-. 0.7 and 3.29 .+-. 0.36 .mu.mol .cntdot. kg body wt-1 .cntdot. min-1, respectively) accounted for .apprx. 30% of their overall disappearance from plasma, whereas alanine and lactate incorporation into plasma glucose (1.83 .+-. 0.20 and 4.24 .+-. 0.44 .mu.mol .cntdot. body wt-1 .cntdot. min-1, respectively) accouted for .apprx. 50% of their disappearance from plasma. We therefore conclude that muscle is the major source of plasma alanine and lactate in postabsorptive humans and that factors regulating their release from muscle may thus exert an important influence on hepatic gluconeogenesis.