García-Martínez C, López-Soriano F J, Argilés J M
Departament de Bioquímica i Fisiologia, Facultat de Biologia, Universitat de Barcelona, Spain.
Mol Cell Biochem. 1995 Jul 5;148(1):17-23. doi: 10.1007/BF00929498.
Rats bearing the Yoshida AH-130 ascites hepatoma show decreased activity of neutral amino acid transport in skeletal muscle measured in vivo as the tissue accumulation of the analogue alpha-amino [1-14C]isobutyrate (AIB). The decreased accumulation of AIB observed is not merely a consequence of the hypoinsulinaemia present in these animals (as a result of tumour burden) since in vitro experiments carried out using incubations of isolated soleus muscles also showed a decreased uptake of neutral amino acids. In these preparations the addition of insulin results in similar increases in uptake both in the pair-fed controls and the tumour-bearing animals, thus suggesting similar insulin sensitivities. The decrease in amino acid uptake in soleus muscle is associated with a decrease in the activity of system A, while systems L and ASC show no particular changes as a result of the tumour growth. The kinetic characterisation of system A in the Yoshida-bearing rats shows a decrease in Vmax together with a decrease in KM in relation with the pair-fed animals.
携带吉田AH - 130腹水肝癌的大鼠，其骨骼肌中中性氨基酸转运活性降低，这在体内通过类似物α - 氨基[1 - 14C]异丁酸（AIB）的组织积累来测定。观察到的AIB积累减少不仅仅是这些动物存在低胰岛素血症（由于肿瘤负荷）的结果，因为使用离体比目鱼肌孵育进行的体外实验也显示中性氨基酸摄取减少。在这些制剂中，添加胰岛素后，成对喂养的对照动物和荷瘤动物的摄取量都有类似增加，因此表明胰岛素敏感性相似。比目鱼肌中氨基酸摄取的减少与A系统活性的降低有关，而L系统和ASC系统在肿瘤生长后没有表现出特别的变化。携带吉田肿瘤大鼠中A系统的动力学特征显示，与成对喂养的动物相比，Vmax降低，同时KM也降低。
