Yoshida S, Ohta J, Shirouzu Y, Ishibashi N, Harada Y, Yamana H, Shirouzu K
First Department of Surgery, Kurume University, School of Medicine, Fukuok, Japan.
Am J Physiol. 1997 Jul;273(1 Pt 1):E10-6. doi: 10.1152/ajpendo.1997.273.1.E10.
The objectives of this study were to evaluate the effect of insulin-like growth factor I (IGF-I) on the fractional synthesis rate (FSR) of muscle and whole body protein breakdown rate (WPBR) during methionine-free total parenteral nutrition (MTPN). We also determined whether the inhibition of endogenous methionine availability reduced tumor protein synthesis. AH109A hepatoma cells were inoculated onto the backs of Donryu rats on day 0. On day 10, the rats were catheterized for TPN and assigned to one of four groups: 1) standard TPN (STPN), 2) STPN + IGF-I, 3) MTPN, or 4) MTPN + IGF-I. The addition of IGF-I to MTPN reduced the loss of body weight by both increasing muscle FSR and reducing WPBR. The tumor FSR did not differ between MTPN + IGF-I and MTPN. The methionine extraction ratio from the liver was negative with MTPN + IGF-I but positive in the other groups. We concluded that IGF-I blockage of endogenous methionine release from peripheral protein sites was associated with a shift to liver-derived methionine, with no change in tumor growth in MTPN-treated rats.
本研究的目的是评估在无蛋氨酸全胃肠外营养（MTPN）期间，胰岛素样生长因子I（IGF-I）对肌肉的蛋白质合成率（FSR）和全身蛋白质分解率（WPBR）的影响。我们还确定了内源性蛋氨酸可用性的抑制是否会降低肿瘤蛋白质合成。在第0天，将AH109A肝癌细胞接种到唐育大鼠的背部。在第10天，将大鼠插入导管进行全胃肠外营养，并分为四组之一：1）标准全胃肠外营养（STPN），2）STPN + IGF-I，3）MTPN，或4）MTPN + IGF-I。在MTPN中添加IGF-I，通过增加肌肉FSR和降低WPBR，减少了体重减轻。MTPN + IGF-I组和MTPN组之间的肿瘤FSR没有差异。MTPN + IGF-I组肝脏的蛋氨酸提取率为负，而其他组为正。我们得出结论，IGF-I阻断外周蛋白部位内源性蛋氨酸的释放与转向肝脏来源的蛋氨酸有关，在接受MTPN治疗的大鼠中肿瘤生长没有变化。
