title: Short-term, increasing dietary protein and fat moderately affect energy expenditure, substrate oxidation and uncoupling protein gene expression in rats.
abstract: Macronutrient composition of diets can influence body-weight development and energy balance. We studied the short-term effects of high-protein (HP) and/or high-fat (HF) diets on energy expenditure (EE) and uncoupling protein (UCP1-3) gene expression. Adult male rats were fed ad libitum with diets containing different protein-fat ratios: adequate protein-normal fat (AP-NF): 20% casein, 5% fat; adequate protein-high fat (AP-HF): 20% casein, 17% fat; high protein-normal fat (HP-NF): 60% casein, 5% fat; high protein-high fat (HP-HF): 60% casein, 17% fat. Wheat starch was used for adjustment of energy content. After 4 days, overnight EE and oxygen consumption, as measured by indirect calorimetry, were higher and body-weight gain was lower in rats fed with HP diets as compared with rats fed diets with adequate protein content (P<.05). Exchanging carbohydrates by protein increased fat oxidation in HF diet fed groups. The UCP1 mRNA expression in brown adipose tissue was not significantly different in HP diet fed groups as compared with AP diet fed groups. Expression of different homologues of UCPs positively correlated with nighttime oxygen consumption and EE. Moreover, dietary protein and fat distinctly influenced liver UCP2 and skeletal muscle UCP3 mRNA expressions. These findings demonstrated that a 4-day ad libitum high dietary protein exposure influences energy balance in rats. A function of UCPs in energy balance and dissipating food energy was suggested. Future experiments are focused on the regulation of UCP gene expression by dietary protein, which could be important for body-weight management.
authors.affiliation: Groups of Stable Isotopes and of Energy Metabolism, German Institute of Human Nutrition in Potsdam-Rehbrücke (DIfE), D-14558 Nuthetal, Germany. petzke@mail.dife.de
authors.forename: Klaus J
authors.initials: KJ
authors.lastname: Petzke
authors.forename: Cornelia
authors.initials: C
authors.lastname: Riese
authors.forename: Susanne
authors.initials: S
authors.lastname: Klaus
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001835:Body Weight; D004041:Dietary Fats / Q000494:pharmacology*; D004044:Dietary Proteins / Q000494:pharmacology*; D004734:Energy Metabolism / Q000187:drug effects*; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D007473:Ion Channels / Q000235:genetics; D024101:Mitochondrial Proteins / Q000235:genetics; D051381:Rats; D011919:Rats, Inbred Strains; D014280:Triglycerides / Q000378:metabolism; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3
chemical_list: D000596:Amino Acids; D004041:Dietary Fats; D004044:Dietary Proteins; D005230:Fatty Acids, Nonesterified; D007473:Ion Channels; D024101:Mitochondrial Proteins; D014280:Triglycerides; C000604371:UCP1 protein, human; C000604389:UCP2 protein, human; C000604392:UCP3 protein, human; C000604373:Ucp1 protein, rat; C000604391:Ucp2 protein, rat; C000604394:Ucp3 protein, rat; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3