Energy restriction only slightly influences protein metabolism in obese rats, whatever the level of protein and its source in the diet.
Summary of "Energy restriction only slightly influences protein metabolism in obese rats, whatever the level of protein and its source in the diet."
BACKGROUND:
High protein (HP) diets during energy restriction have been studied extensively regarding their ability to reduce body fat and preserve lean body mass, but little is known about their effects on protein metabolism in lean tissues.
OBJECTIVE:
To determine the effects of energy restriction and protein intake on protein anabolism and catabolism in rats.
METHODS:
For 5 weeks, 56 male Wistar rats were fed an obesity induction (OI) diet . They were then subjected to a 40% energy restriction using the OI diet or a balanced HP diet for 3 weeks, whereas a control group was fed the OI diet ad libitum (n=8 per group). HP-restricted rats were divided into five groups differing only in terms of their protein source: total milk proteins, casein (C), whey (W), a mix of 50% C and W, and soy (n=8). The animals were then killed in the postprandial state and their body composition was determined. Protein synthesis rates were determined in the liver, gastrocnemius and kidney using a subcutaneous (13)C valine flooding dose. mRNA levels were measured for key enzymes involved in the three proteolysis pathways.
RESULTS:
Energy restriction, but not diet composition, impacted weight loss and adiposity, whereas lean tissue mass (except in the kidney) was not influenced by diet composition. Levels of neoglucogenic amino acids tended to fall under energy restriction (P<0.06) but this was reversed by a high level of protein. The postprandial protein synthesis rates in different organs were similar in all groups. By contrast, mRNA levels encoding proteolytic enzymes rose under energy restriction in the muscle and kidney, but this was counteracted by a HP level.
CONCLUSIONS:
In adult obese rats, energy restriction but not diet composition affected fat pads and had little impact on protein metabolism, despite marked effects on proteolysis in the kidney and muscle.International Journal of Obesity advance online publication, 21 February 2012; doi:10.1038/ijo.2012.19.
Affiliation
1] INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, AgroParisTech, Paris, France [2] AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France.
Journal Details
This article was published in the following journal.
Name: International journal of obesity (2005)
ISSN: 1476-5497
Pages:
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22349571
- DOI: http://dx.doi.org/10.1038/ijo.2012.19
Medical and Biotech [MESH] Definitions
Amp-activated Protein Kinases
Intracellular signaling protein kinases that play a signaling role in the regulation of cellular energy metabolism. Their activity largely depends upon the concentration of cellular AMP which is increased under conditions of low energy or metabolic stress. AMP-activated protein kinases modify enzymes involved in LIPID METABOLISM, which in turn provide substrates needed to convert AMP into ATP.
Bioelectric Energy Sources
Electric power supply devices which convert biological energy, such as chemical energy of metabolism or mechanical energy of periodic movements, into electrical energy.
Optical Restriction Mapping
A technique to generate restriction maps from single large DNA molecules by spreading the DNA onto a glass surface, digesting with DNA RESTRICTION ENZYMES, staining with FLUORESCENT DYES, and visualizing the DNA cleavage sites by FLUORESCENCE MICROSCOPY.
Energy Metabolism
The chemical reactions involved in the production and utilization of various forms of energy in cells.
Dna Restriction-modification Enzymes
Systems consisting of two enzymes, a modification methylase and a restriction endonuclease. They are closely related in their specificity and protect the DNA of a given bacterial species. The methylase adds methyl groups to adenine or cytosine residues in the same target sequence that constitutes the restriction enzyme binding site. The methylation renders the target site resistant to restriction, thereby protecting DNA against cleavage.
PubMed Articles
Abstract Aim: Uncoupling protein (UCP) genes, which may contribute to energy metabolism in mitochondria, may be involved in the pathogenesis of obesity. We analyzed the differences in energy expenditu...
ABSTRACT: Insufficient calcium intake has been proposed to cause unbalanced energy partitioning leading to obesity. However, weight loss interventions including dietary calcium or dairy product consum...
The purpose of this study was to determine the effects of dietary protein and eating frequency on perceived appetite and satiety during weight loss. A total of 27 overweight/obese men (age 47 ± 3 yea...
To determine the effects of food restriction (FR) on the expression of Sirt1 and its down-stream factors related to lipid and glucose metabolism in obese and hypertensive rats (SHRSP/IDmcr-fa), as a m...
The objective was to investigate the effects of a 3-week weight-management program including moderate energy restriction and exercise training at two intensities (LI:40% and HI:70% V'O2max) on body co...
Clinical Trials
The Effect of Weight Loss and Dietary Protein Intake on Bone
The purpose of this study is to learn how the amount of protein during moderate weight loss influences bone health.
Aim: To dissociate the effects on plasma concentrations of the inflammatory marker c-reactive protein of a negative energy balance and a reduction in body fat stores. Secondly to compare C...
Nutritional Restriction and Activity Thermogenesis
These studies will provide us with enormous insight regarding how obese patients adapt energetically during negative energy balance. We will gain fundamental information regarding the met...
To Assess the Effect of Lorcaserin Hydrochloride on Energy Metabolism and Food Intake
The purpose of this study is to evaluate the effect of lorcaserin on energy metabolism and food intake in obese and overweight patients.
The Protein (Meat) and Function Study
The aim of the proposed study is to investigate the effects of different amounts of protein intake primarily from meat on muscle function, immune response, mental function, proteomics, bio...
