去甲硫氨酸/缬氨酸喂饲荷瘤大鼠对其在体内分布及核酸、蛋白质代谢的影响  

Influence of the methionine/valine-depleted enteral nutrition on tissue distribution,nucleic acids and protein metabolism in tumor-bearing rats

作　　者：贺银成[1] 周亚魁[1] 黎文[2] 陈纪伟[1] 乔建国[1] 

机构地区：[1]武汉大学中南医院普外科,湖北武汉430071 [2]临床外科杂志社

出　　处：《肠外与肠内营养》2001年第3期161-164,共4页Parenteral & Enteral Nutrition

摘　　要：目的 :观察去甲硫氨酸 /缬氨酸空肠喂饲荷瘤大鼠对其在体内分布及核酸、蛋白质代谢的影响。　方法 :SD大鼠空肠造口 ,皮下接种 Walker- 2 5 6癌肉瘤 ,分 A、B、C、D四组。分别以平衡氨基酸、去蛋氨酸、平衡氨基酸和去缬氨酸空肠喂养 6天 ,注入 3H-甲硫氨酸 /缬氨酸 (3H- Met/ Val) 7.4× 10 5 Bq,0 .5、1、2、4h后分别测定肿瘤组织 RNA、DNA及蛋白质的 3H掺入率 ,测定各时点肝、胰、小肠、肌肉、血浆及肿瘤组织的放射性强度 ,计算差示摄取比 (dif-ferential uptake ratios,DUR)。　结果 :1B组肿瘤组织对 3H- Met摄取率 2、4h分别为 (8.0 9± 0 .12 ) %及 (7.81±0 .17) % ,高于 A组的 (6 .5 9± 0 .2 4) %及 (6 .16± 0 .0 6 ) % (P<0 .0 1) ;而 B组血浆 3H- Met摄取率各时点均低于 A组。 D组肿瘤组织 3H- Val摄取率平均为 (7.33± 0 .6 9) % ,高于 C组的 (6 .2 3± 0 .74% ) (P<0 .0 5 ) ;而血浆摄取率为(0 .70± 0 .12 ) %低于 C组 (1.0 2± 0 .0 2 ) %。 2缺乏甲硫氨酸 /缬氨酸时 ,其他组织对 3H- Met/ Val摄取率影响不大。3B、D组蛋白质及 B组 RNA、DNA的 3H- Met/ Val掺入率均低于各自对照组。　结论 :去甲硫氨酸 /缬氨酸空肠喂饲荷瘤大鼠 ,肿瘤组织 3H- Met/ Val摄取率升高 ,血浆摄取率降低 。Objectives:To investigate effect of the methionine/valine(Met/Val) depleted enteral nutrition on tissue distribution,RNA,DNA and protein metabolism in tumor bearing(TB) rats. Methods:SD rats underwent catheterization of jejunostomy.A suspension of Walker 256 sarcocarcinoma cells was subcutaneously inoculated.The TB rats were randomly divided into 4 groups:A,B,C and D.The TB rats received jejunostomy feedings supplemented with balanced amino acid,methionine/valine depleted nutnition for 6 days before injection of 7.4×10 5 Bq 3H methionine/vatine.The tissue uptake and 3H Incorporation rate of radioactity into RNA,DNA and proteins in tumor tissues at 0.5,1,2,4 h after injection were assessed. Results:①Uptakes of 3H by tumor tissues in group B at 2,4 h after injection were (8.09±0.12)% and (7.81±0.17)% respectively and they were (6.59±0.24)% and (6.16±0.06)% in group A( P <0.01).The total uptake of 3H by plasma in group B was lower than in group A.In group D,tissue upatke of 3H Val was (7.33±0.69)% by tumor and (0.70±0.12)% by plasma.But they were (6.23±0.74)% and (1.02±0.02)% respectively in group C( P <0.05). ②The uptakes of 3H by other organs were not significantly different in groups B and C compared with control groups.③Incorporations of 3H into proteins in groups B and D or into RNA and DNA in group B were lower than in control groups. Conclusions:Upatke of 3H Met/Val by tumor tissue in TB rats is increased after Methionine/Valine depleted enteral nutrition treatment.Protein and nucleic acid syntheses are inhibited by methionine/valine starvation in TB rats.

关 键 词：氨基酸 甲硫氨酸 缬氨酸 DNA 肿瘤/实验性 

分 类 号：Q517[生物学—生物化学]