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Amino acid‐induced impairment of insulin sensitivity in healthy and obese rats is reversible
High‐protein diets (HPDs) promote weight loss but other studies implicate these diets and their constituent amino acids (AAs) in insulin resistance. We hypothesized that AA‐induced insulin resistance is a temporal and reversible metabolic event. L6 myotubes were serum deprived for 4 h and then incub...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Wiley Periodicals, Inc.
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4187556/ https://www.ncbi.nlm.nih.gov/pubmed/24997070 http://dx.doi.org/10.14814/phy2.12067 |
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author | Jeganathan, Senthure Abdullahi, Abdikarim Zargar, Sana Maeda, Naomi Riddell, Michael C. Adegoke, Olasunkanmi A. J. |
author_facet | Jeganathan, Senthure Abdullahi, Abdikarim Zargar, Sana Maeda, Naomi Riddell, Michael C. Adegoke, Olasunkanmi A. J. |
author_sort | Jeganathan, Senthure |
collection | PubMed |
description | High‐protein diets (HPDs) promote weight loss but other studies implicate these diets and their constituent amino acids (AAs) in insulin resistance. We hypothesized that AA‐induced insulin resistance is a temporal and reversible metabolic event. L6 myotubes were serum deprived for 4 h and then incubated in AA and/or insulin (100 nmol/L). Another group of cells was incubated overnight in AA + insulin, starved again, and then reincubated with AA and insulin. Mammalian (mechanistic) target of rapamycin complex 1 (mTORC1) signaling and glucose uptake were then measured. Healthy or insulin‐resistant rats were gavaged with leucine (0.48 g/kg) and insulin sensitivity was examined. In myotubes, incubation with AA and insulin significantly (P <0.05) increased the phosphorylation of the mTORC1 substrate ribosomal protein S6 kinase 1 (S6K1, T389) and of insulin receptor substrate 1 (IRS‐1, serine residues), but suppressed insulin‐stimulated glucose uptake by 40% (P <0.01). These modifications were mTORC1‐dependent and were reversible. In vivo, leucine gavage reversibly increased S6K1 phosphorylation and IRS‐1 serine phosphorylation 5‐ to 12‐fold in skeletal muscle and impaired insulin tolerance of glucose (P <0.05) in lean rats. In insulin‐resistant rats, the impairment of whole blood glucose and AA metabolism induced by leucine gavage (0.001 < P <0.05) was more severe than that observed in lean rats; however, the impairment was reversible within 24 h of treatment. If these data are confirmed in long‐term studies, it would imply that the use of leucine/HPD in treating metabolic diseases is unlikely to have lasting negative effects on insulin sensitivity. |
format | Online Article Text |
id | pubmed-4187556 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | Wiley Periodicals, Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-41875562014-11-12 Amino acid‐induced impairment of insulin sensitivity in healthy and obese rats is reversible Jeganathan, Senthure Abdullahi, Abdikarim Zargar, Sana Maeda, Naomi Riddell, Michael C. Adegoke, Olasunkanmi A. J. Physiol Rep Original Research High‐protein diets (HPDs) promote weight loss but other studies implicate these diets and their constituent amino acids (AAs) in insulin resistance. We hypothesized that AA‐induced insulin resistance is a temporal and reversible metabolic event. L6 myotubes were serum deprived for 4 h and then incubated in AA and/or insulin (100 nmol/L). Another group of cells was incubated overnight in AA + insulin, starved again, and then reincubated with AA and insulin. Mammalian (mechanistic) target of rapamycin complex 1 (mTORC1) signaling and glucose uptake were then measured. Healthy or insulin‐resistant rats were gavaged with leucine (0.48 g/kg) and insulin sensitivity was examined. In myotubes, incubation with AA and insulin significantly (P <0.05) increased the phosphorylation of the mTORC1 substrate ribosomal protein S6 kinase 1 (S6K1, T389) and of insulin receptor substrate 1 (IRS‐1, serine residues), but suppressed insulin‐stimulated glucose uptake by 40% (P <0.01). These modifications were mTORC1‐dependent and were reversible. In vivo, leucine gavage reversibly increased S6K1 phosphorylation and IRS‐1 serine phosphorylation 5‐ to 12‐fold in skeletal muscle and impaired insulin tolerance of glucose (P <0.05) in lean rats. In insulin‐resistant rats, the impairment of whole blood glucose and AA metabolism induced by leucine gavage (0.001 < P <0.05) was more severe than that observed in lean rats; however, the impairment was reversible within 24 h of treatment. If these data are confirmed in long‐term studies, it would imply that the use of leucine/HPD in treating metabolic diseases is unlikely to have lasting negative effects on insulin sensitivity. Wiley Periodicals, Inc. 2014-07-04 /pmc/articles/PMC4187556/ /pubmed/24997070 http://dx.doi.org/10.14814/phy2.12067 Text en © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society. http://creativecommons.org/licenses/by/3.0/ This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Research Jeganathan, Senthure Abdullahi, Abdikarim Zargar, Sana Maeda, Naomi Riddell, Michael C. Adegoke, Olasunkanmi A. J. Amino acid‐induced impairment of insulin sensitivity in healthy and obese rats is reversible |
title | Amino acid‐induced impairment of insulin sensitivity in healthy and obese rats is reversible |
title_full | Amino acid‐induced impairment of insulin sensitivity in healthy and obese rats is reversible |
title_fullStr | Amino acid‐induced impairment of insulin sensitivity in healthy and obese rats is reversible |
title_full_unstemmed | Amino acid‐induced impairment of insulin sensitivity in healthy and obese rats is reversible |
title_short | Amino acid‐induced impairment of insulin sensitivity in healthy and obese rats is reversible |
title_sort | amino acid‐induced impairment of insulin sensitivity in healthy and obese rats is reversible |
topic | Original Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4187556/ https://www.ncbi.nlm.nih.gov/pubmed/24997070 http://dx.doi.org/10.14814/phy2.12067 |
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