Ventrucci G, Mello M A, Gomes-Marcondes M C
Departamento de Fisiologia e Biofísica, Instituto de Biologia, Universidade de Campinas, Campinas, SP, Brasil.
Braz J Med Biol Res. 2001 Mar;34(3):333-8. doi: 10.1590/s0100-879x2001000300006.
Cancer patients present high mobilization of host protein, with a decrease in lean body mass and body fat depletion occurring in parallel to neoplastic growth. Since leucine is one of the principal amino acids used by skeletal muscle for energy, we investigated the changes in body composition of pregnant tumor-bearing rats after a leucine-supplemented diet. Sixty pregnant Wistar rats divided into six groups were fed a normal protein diet (18%, N) or a leucine-supplemented diet (3% L-leucine, L). The pregnant groups were: control (CN), Walker 256 carcinoma-bearing rats (WN), control rats pair-fed with tumor-bearing rats (pfN), leucine-supplemented (CL), leucine-supplemented tumor-bearing (WL), and leucine-supplemented rats pair-fed with tumor-bearing rats (pfL). At the end of pregnancy, all animals were sacrificed and body weight and tumor and fetal weight were determined. The carcasses were then analyzed for water, fat and total, collagen and non-collagen nitrogen content. Carcass weight was reduced in the WN, WL, pfN and pfL groups compared to control. The lean body mass and total carcass nitrogen were reduced in both tumor-bearing groups. Despite tumor growth and a decrease in fetal weight, there was a slight decrease in collagen (7%) and non-collagen nitrogen (8%) in the WL group compared with the WN group which showed a decrease of 8 and 12%, respectively. Although the WL group presented severe tumor growth effects, total carcass nitrogen and non-collagen nitrogen were particularly higher in this leucine-supplemented group compared to the WN group. These data suggest that the leucine-supplemented diet had a beneficial effect, probably attenuating body wasting.
癌症患者体内宿主蛋白的动员率很高，瘦体重的减少和体脂的消耗与肿瘤生长同时发生。由于亮氨酸是骨骼肌用于能量代谢的主要氨基酸之一，我们研究了补充亮氨酸饮食后怀孕的荷瘤大鼠的身体组成变化。将60只怀孕的Wistar大鼠分为六组，分别给予正常蛋白质饮食（18%，N）或补充亮氨酸的饮食（3% L-亮氨酸，L）。怀孕组包括：对照组（CN）、携带Walker 256癌的大鼠（WN）、与荷瘤大鼠配对喂养的对照大鼠（pfN）、补充亮氨酸组（CL）、补充亮氨酸的荷瘤组（WL）以及与荷瘤大鼠配对喂养的补充亮氨酸组（pfL）。妊娠末期，处死所有动物，测定体重、肿瘤重量和胎儿重量。然后分析尸体的水分、脂肪以及总氮、胶原蛋白氮和非胶原蛋白氮含量。与对照组相比，WN、WL、pfN和pfL组的尸体重量降低。两个荷瘤组的瘦体重和尸体总氮含量均降低。尽管肿瘤生长且胎儿体重下降，但与分别降低了8%和12%的WN组相比，WL组的胶原蛋白（7%）和非胶原蛋白氮（8%）略有下降。尽管WL组呈现出严重的肿瘤生长效应，但与WN组相比，该补充亮氨酸组的尸体总氮和非胶原蛋白氮含量尤其更高。这些数据表明，补充亮氨酸的饮食具有有益作用，可能减轻了身体消瘦。
