论文部分内容阅读
谷氨酰胺在维持体内氮内稳定中占关键地位.因肿瘤主要消耗谷氨酰胺,而且某些组织中谷氨酰胺需要量增加,故癌宿主的体内氮内稳定受到威胁,谷氨酸胺缺乏,在癌症恶液质也起一定作用.例如在荷瘤大鼠的肌谷氨酰胺流出就加速,不单是由于进食量减少.肝在癌宿主体内维持谷氨酰胺内稳定中起主要作用,根据机体需要,以作为净谷氨酰胺消耗器官或生成器官来应答.肿瘤小(瘤体占体重5～10%)的大鼠,肝为净生成谷氨酰胺,这一输出更多谷氨酰胺的能力是由于一种新的高度选择性,与肝细胞膜结合的,钠离子非依赖性转运体,称为n系统,其功能为将谷氨酰胺转运出细胞,进入血液.而输入谷氨酰胺的称N系统.在荷瘤大鼠的n系统活性增加,但其调节机制未明.作者认为可能与血内谷氨酰胺浓度下降有关.
Glutamine plays a key role in maintaining the stability of nitrogen in the body. Because the tumor mainly consumes glutamine and the glutamine requirement in some tissues increases, the stability of the nitrogen in the cancer host is threatened, and the glutamate amine is lacking. It also plays a role in cancer cachexia. For example, muscle glutamine outflow in tumor-bearing rats accelerates, not only because of reduced feed intake. The liver plays a major role in maintaining the stability of glutamine within the cancer host, according to the body. Need to respond as a net glutamine depletion organ or producing organ. Rats with small tumors (5 to 10% of body weight) have a net production of glutamine in the liver, which is more glutamine exportable It is due to a new highly selective, sodium-ion-independent transporter that binds to the hepatocyte membrane and is called the n-system. Its function is to transport glutamine out of the cell and into the blood. The input of glutamine is called N system. In the tumor-bearing rat n system activity increased, but its regulation mechanism is unknown. The author believes that may be related to the decrease of blood glutamine concentration.