Reduced glucose‐induced insulin secretion in low‐protein‐fed rats is associated with altered pancreatic islets redox status |
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| Authors: | Ana Paula G Cappelli Claudio C Zoppi Leonardo R Silveira Thiago M Batista Flávia M Paula Priscilla M R da Silva Alex Rafacho Helena C Barbosa‐Sampaio Antonio C Boschero Everardo M Carneiro |
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| Institution: | 1. Department of Structural and Functional Biology, Cellular Biology and Physiology and Biophysics, Institute of Biology, University of Campinas (UNICAMP), Campinas, S?o Paulo, Brazil;2. Laboratory of Experimental Physiology, Department of Physiological Sciences, Federal University of Maranh?o (UFMA), S?o Luís, Maranh?o, Brazil;3. Department of Physiology and Biophysiology, Institute of Biomedical Sciences, University of Sao Paulo (USP), S?o Paulo, Brazil;4. Department of Physiologic Sciences, Center of Biologic Sciences, Federal University of Santa Catarina (UFSC), Florianopolis, Santa Catarina, Brazil |
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| Abstract: | In the present study, we investigated the relationship between early life protein malnutrition‐induced redox imbalance, and reduced glucose‐stimulated insulin secretion. After weaning, male Wistar rats were submitted to a normal‐protein‐diet (17%‐protein, NP) or to a low‐protein‐diet (6%‐protein, LP) for 60 days. Pancreatic islets were isolated and hydrogen peroxide (H2O2), oxidized (GSSG) and reduced (GSH) glutathione content, CuZn‐superoxide dismutase (SOD1), glutathione peroxidase (GPx1) and catalase (CAT) gene expression, as well as enzymatic antioxidant activities were quantified. Islets that were pre‐incubated with H2O2 and/or N‐acetylcysteine, were subsequently incubated with glucose for insulin secretion measurement. Protein malnutrition increased CAT mRNA content by 100%. LP group SOD1 and CAT activities were 50% increased and reduced, respectively. H2O2 production was more than 50% increased whereas GSH/GSSG ratio was near 60% lower in LP group. Insulin secretion was, in most conditions, approximately 50% lower in LP rat islets. When islets were pre‐incubated with H2O2 (100 μM), and incubated with glucose (33 mM), LP rats showed significant decrease of insulin secretion. This effect was attenuated when LP islets were exposed to N‐acetylcysteine. |
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| Keywords: | antioxidant enzymes insulin secretion pancreatic islets protein malnutrition reactive oxygen species |
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