Roth E, Valentini L, Hölzenbein T, Winkler S, Sautner T, Hörtnagl H, Karner J
Institute of Biochemical Pharmacology, University of Vienna, Australia.
Biochem J. 1993 Dec 15;296 ( Pt 3)(Pt 3):765-9. doi: 10.1042/bj2960765.
The effects of acute administration of human recombinant insulin-like growth factor-I (rhIGF-I) on amino acid (AA) flux between hindlimbs, liver and gut were investigated in anaesthetized post-operative dogs. rhIGF-I produced about a 10-fold increase in plasma IGF-I concentrations above baseline values (P < 0.001), increased the plasma levels of glucagon and adrenaline (P < 0.05), and evoked a fall in plasma glucose (-55 +/- 8%; (P < 0.001) and plasma total AA levels (-23 +/- 8%; P < 0.05). AA flux in post-absorptive dogs under NaCl infusions was characterized by an efflux of AA from the hindlimbs (as a result of the protein-catabolic situation), an equal AA balance across the gut and an AA uptake by the liver. The administration of rhIGF-I increased hepatic AA uptake in the NaCl group from 3.51 +/- 0.8 to 7.5 +/- 0.4 mumol/min per kg (P < 0.01) and in the AA-infused group from 16.8 +/- 0.6 to 22.4 +/- 1.5 mumol/min per kg (P < 0.05), but did not influence the AA balance across hindlimbs and gut. Glucose infusions normalized the plasma concentrations of counter-regulatory hormones without influencing the inter-organ AA balances. We conclude that hypoaminoacidaemia caused by rhIGF-I infusions is the result of a stimulated AA uptake by the liver, but is unrelated to alterations of AA exchange across the hindlimbs.
在麻醉的术后犬中研究了急性给予人重组胰岛素样生长因子-I（rhIGF-I）对后肢、肝脏和肠道之间氨基酸（AA）通量的影响。rhIGF-I使血浆IGF-I浓度比基线值增加了约10倍（P<0.001），增加了胰高血糖素和肾上腺素的血浆水平（P<0.05），并导致血浆葡萄糖下降（-55±8%；P<0.001）和血浆总AA水平下降（-23±8%；P<0.05）。在输注氯化钠的情况下，处于吸收后状态的犬的AA通量的特征是AA从后肢流出（由于蛋白质分解代谢状态）、肠道AA平衡相等以及肝脏摄取AA。给予rhIGF-I使氯化钠组肝脏AA摄取量从3.51±0.8增加到7.5±0.4μmol/（min·kg）（P<0.01），在输注AA的组中从16.8±0.6增加到22.4±1.5μmol/（min·kg）（P<0.05），但不影响后肢和肠道的AA平衡。输注葡萄糖使血浆中反调节激素的浓度正常化，而不影响器官间的AA平衡。我们得出结论，rhIGF-I输注引起的低氨基酸血症是肝脏对AA摄取增加的结果，但与后肢AA交换的改变无关。
