title: Mitochondrial energetics in liver and skeletal muscle after energy restriction in young rats.
abstract: The present study investigated the effect of 2 weeks of energy restriction on whole body, liver and skeletal muscle energy handling. We measured whole-body oxygen consumption, as well as mitochondrial protein mass, respiratory capacity and energetic coupling in liver and skeletal muscle from food-restricted (FR) rats, age- and weight-matched controls. We also assessed markers of oxidative damage and antioxidant defences. The present results show that, in response to energy restriction, an adaptive decrease in whole-body energy expenditure is coupled with structural and functional changes in mitochondrial compartment, both in liver and skeletal muscle. In fact, liver mitochondrial mass per g of liver significantly increased, whereas total hepatic mitochondrial oxidative capacity was lower in FR than in control rats, because of a significant decrease in liver contribution to total body weight. In skeletal muscle, sub-sarcolemmal (SS) mitochondrial respiratory capacity, as well as SS and inter-myofibrillar (IMF) mitochondrial protein mass per g of tissue, was significantly lower in FR rats, compared to controls. Finally, a decrease in oxidative damage was found in liver but not in skeletal muscle mitochondria from FR rats, whereas an increase in antioxidant defence was found in both tissues. From the present results, it appears that skeletal muscle is involved in the decrease in energy expenditure induced by energy restriction. Energy sparing is achieved through changes in the activity (SS), mass (SS and IMF) and efficiency (IMF) of mitochondrial compartment.
authors.affiliation: Department of Structural and Functional Biology, University of Naples, Complesso Universitario di Monte Sant'Angelo, Napoli, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Crescenzo
authors.forename: Francesca
authors.initials: F
authors.lastname: Bianco
authors.forename: Italia
authors.initials: I
authors.lastname: Falcone
authors.forename: Paola
authors.initials: P
authors.lastname: Coppola
authors.forename: Abdul G
authors.initials: AG
authors.lastname: Dulloo
authors.forename: Giovanna
authors.initials: G
authors.lastname: Liverini
authors.forename: Susanna
authors.initials: S
authors.lastname: Iossa
mesh_terms: D000154:Aconitate Hydratase / Q000378:metabolism; D000818:Animals; D031204:Caloric Restriction / Q000009:adverse effects; D002245:Carbon Dioxide / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000378:metabolism; D015227:Lipid Peroxidation; D008099:Liver / Q000033:anatomy & histology / Q000201:enzymology / Q000378:metabolism; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology / Q000378:metabolism*; D008931:Mitochondria, Muscle / Q000201:enzymology / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000201:enzymology / Q000378:metabolism*; D009929:Organ Size; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D002245:Carbon Dioxide; D045304:Cytochromes c; D013482:Superoxide Dismutase; D003576:Electron Transport Complex IV; D000154:Aconitate Hydratase