title: Leucine improves protein nutritional status and regulates hepatic lipid metabolism in calorie-restricted rats.
abstract: Several studies have highlighted the potential of leucine supplementation for the treatment of metabolic diseases including type 2 diabetes and obesity. Caloric restriction is a common approach to improve the health in diabetic and obese subjects. However, very few studies assessed the effects of leucine supplementation in calorie-restricted animals. Rats were subjected to a 30% calorie-restricted diet for 6 weeks to study the effects of leucine supplementation on protein status markers and lipid metabolism. Caloric restriction reduced the body weight. However, increased leucine intake preserved body lean mass and protein mass and improved protein anabolism as indicated by the increased circulating levels of albumin and insulin-like growth factor-1 (IGF-1), and the liver expression of albumin and IGF-1 messenger RNA. Leucine supplementation also increased the circulating levels of interleukin-6 and leptin but did not affect the tumour necrosis factor-α and monocyte chemotactic protein-1 concentrations. Ketone bodies were increased in rats consuming a leucine-rich diet, but we observed no changes in cholesterol or triglycerides concentrations. Caloric restriction reduced the liver expression of peroxisome proliferator activated receptor-α and glucose-6-phosphatase, whereas leucine supplementation increased the liver expression of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA) reductase and sterol regulatory element-binding transcription factor 1. A leucine-rich diet during caloric restriction preserved whole body protein mass and improved markers of protein anabolism. In addition, leucine modulated the hepatic lipid metabolism. These results indicate that increased leucine intake may be useful in preventing excessive protein waste in conditions of large weight loss.
authors: Department of Food Science and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil; Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
authors: João Alfredo B
authors: JA
authors: Pedroso
authors: Luciana Sigueta
authors: LS
authors: Nishimura
authors: Emídio Marques
authors: EM
authors: de Matos-Neto
authors: Jose
authors: J
authors: Donato
authors: Julio
authors: J
authors: Tirapegui
mesh_terms: D000418:Albumins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001823:Body Composition; D031204:Caloric Restriction; D019587:Dietary Supplements; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D015850:Interleukin-6 / Q000097:blood; D007657:Ketone Bodies / Q000378:metabolism; D020738:Leptin / Q000097:blood; D007930:Leucine / Q000494:pharmacology*; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D009752:Nutritional Status; D012333:RNA, Messenger / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D000418:Albumins; D015415:Biomarkers; D015850:Interleukin-6; D007657:Ketone Bodies; D020738:Leptin; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D007334:Insulin-Like Growth Factor I; D007930:Leucine
keywords: IGF-1; albumin; branched-chain amino acids; caloric restriction; interleukin-6; supplementation