A leucine-supplemented diet improved protein content of skeletal muscle in young tumor-bearing rats
Cancer cachexia induces host protein wastage but the mechanisms are poorly understood. Branched-chain amino acids play a regulatory role in the modulation of both protein synthesis and degradation in host tissues. Leucine, an important amino acid in skeletal muscle, is higher oxidized in tumor-beari...
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| Format: | Article |
| Language: | English |
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Associação Brasileira de Divulgação Científica
2003-11-01
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| Series: | Brazilian Journal of Medical and Biological Research |
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| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003001100017 |
| _version_ | 1818151871235227648 |
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| author | M.C.C. Gomes-Marcondes G. Ventrucci M.T. Toledo L. Cury J.C. Cooper |
| author_facet | M.C.C. Gomes-Marcondes G. Ventrucci M.T. Toledo L. Cury J.C. Cooper |
| author_sort | M.C.C. Gomes-Marcondes |
| collection | DOAJ |
| description | Cancer cachexia induces host protein wastage but the mechanisms are poorly understood. Branched-chain amino acids play a regulatory role in the modulation of both protein synthesis and degradation in host tissues. Leucine, an important amino acid in skeletal muscle, is higher oxidized in tumor-bearing animals. A leucine-supplemented diet was used to analyze the effects of Walker 256 tumor growth on body composition in young weanling Wistar rats divided into two main dietary groups: normal diet (N, 18% protein) and leucine-rich diet (L, 15% protein plus 3% leucine), which were further subdivided into control (N or L) or tumor-bearing (W or LW) subgroups. After 12 days, the animals were sacrificed and their carcass analyzed. The tumor-bearing groups showed a decrease in body weight and fat content. Lean carcass mass was lower in the W and LW groups (W = 19.9 ± 0.6, LW = 23.1 ± 1.0 g vs N = 29.4 ± 1.3, L = 28.1 ± 1.9 g, P < 0.05). Tumor weight was similar in both tumor-bearing groups fed either diet. Western blot analysis showed that myosin protein content in gastrocnemius muscle was reduced in tumor-bearing animals (W = 0.234 ± 0.033 vs LW = 0.598 ± 0.036, N = 0.623 ± 0.062, L = 0.697 ± 0.065 arbitrary intensity, P < 0.05). Despite accelerated tumor growth, LW animals exhibited a smaller reduction in lean carcass mass and muscle myosin maintenance, suggesting that excess leucine in the diet could counteract, at least in part, the high host protein wasting in weanling tumor-bearing rats. |
| first_indexed | 2024-12-11T13:45:42Z |
| format | Article |
| id | doaj.art-ccda9f7aedbe4420aebb36b1167d01f2 |
| institution | Directory Open Access Journal |
| issn | 0100-879X 1414-431X |
| language | English |
| last_indexed | 2024-12-11T13:45:42Z |
| publishDate | 2003-11-01 |
| publisher | Associação Brasileira de Divulgação Científica |
| record_format | Article |
| series | Brazilian Journal of Medical and Biological Research |
| spelling | doaj.art-ccda9f7aedbe4420aebb36b1167d01f22022-12-22T01:04:32ZengAssociação Brasileira de Divulgação CientíficaBrazilian Journal of Medical and Biological Research0100-879X1414-431X2003-11-0136111589159410.1590/S0100-879X2003001100017A leucine-supplemented diet improved protein content of skeletal muscle in young tumor-bearing ratsM.C.C. Gomes-MarcondesG. VentrucciM.T. ToledoL. CuryJ.C. CooperCancer cachexia induces host protein wastage but the mechanisms are poorly understood. Branched-chain amino acids play a regulatory role in the modulation of both protein synthesis and degradation in host tissues. Leucine, an important amino acid in skeletal muscle, is higher oxidized in tumor-bearing animals. A leucine-supplemented diet was used to analyze the effects of Walker 256 tumor growth on body composition in young weanling Wistar rats divided into two main dietary groups: normal diet (N, 18% protein) and leucine-rich diet (L, 15% protein plus 3% leucine), which were further subdivided into control (N or L) or tumor-bearing (W or LW) subgroups. After 12 days, the animals were sacrificed and their carcass analyzed. The tumor-bearing groups showed a decrease in body weight and fat content. Lean carcass mass was lower in the W and LW groups (W = 19.9 ± 0.6, LW = 23.1 ± 1.0 g vs N = 29.4 ± 1.3, L = 28.1 ± 1.9 g, P < 0.05). Tumor weight was similar in both tumor-bearing groups fed either diet. Western blot analysis showed that myosin protein content in gastrocnemius muscle was reduced in tumor-bearing animals (W = 0.234 ± 0.033 vs LW = 0.598 ± 0.036, N = 0.623 ± 0.062, L = 0.697 ± 0.065 arbitrary intensity, P < 0.05). Despite accelerated tumor growth, LW animals exhibited a smaller reduction in lean carcass mass and muscle myosin maintenance, suggesting that excess leucine in the diet could counteract, at least in part, the high host protein wasting in weanling tumor-bearing rats.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003001100017LeucineAmino acidWalker 256 carcinosarcomaBody compositionSkeletal muscle protein |
| spellingShingle | M.C.C. Gomes-Marcondes G. Ventrucci M.T. Toledo L. Cury J.C. Cooper A leucine-supplemented diet improved protein content of skeletal muscle in young tumor-bearing rats Brazilian Journal of Medical and Biological Research Leucine Amino acid Walker 256 carcinosarcoma Body composition Skeletal muscle protein |
| title | A leucine-supplemented diet improved protein content of skeletal muscle in young tumor-bearing rats |
| title_full | A leucine-supplemented diet improved protein content of skeletal muscle in young tumor-bearing rats |
| title_fullStr | A leucine-supplemented diet improved protein content of skeletal muscle in young tumor-bearing rats |
| title_full_unstemmed | A leucine-supplemented diet improved protein content of skeletal muscle in young tumor-bearing rats |
| title_short | A leucine-supplemented diet improved protein content of skeletal muscle in young tumor-bearing rats |
| title_sort | leucine supplemented diet improved protein content of skeletal muscle in young tumor bearing rats |
| topic | Leucine Amino acid Walker 256 carcinosarcoma Body composition Skeletal muscle protein |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003001100017 |
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