title: Hepatic mitochondrial efficiency in lines of mice differing in feed intake.
abstract: Selection was practiced for high (MH) and low (ML) heat loss using direct calorimetry to create lines of mice differing in feed intake per unit average BW (FI/BW). A total of 25 generations of selection was practiced during maintenance of an unselected control (MC). As a percentage of MC, mice of MH and ML lines differed in heat loss and FI/BW by 56 and 34%, respectively, when selection ceased. The purpose of this study was to determine hepatic mitochondrial efficiency in mice at maintenance across the genetic lines. After measurement of feed intakeand BW over a 2-wk period, mice were euthanized, and their livers were extracted. Livers were homogenized and mitochondria were isolated in buffer for measurement of oxygen consumption and, hence, mitochondrial activity using a Clark-type oxygen electrode. Mitochondria of ML mice expressed greater (P < 0.03) respiratory control ratio by 22% than that for MH mice, revealing greater degree of uncoupling during electron transport in MH mice. Difference in FI/BW (P < 0.001) was large with MH mice consuming 34% more than ML mice. The respiratory control ratio differed between mice of MH and ML lines as expected; however, regression analysis revealed that it explained essentially no variation in feed intake per BW.
authors: Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE 68583-0908, USA.
authors: T W
authors: TW
authors: Murphy
authors: J M
authors: JM
authors: McDonald
authors: M K
authors: MK
authors: Nielsen
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001823:Body Composition; D001833:Body Temperature Regulation; D001835:Body Weight; D019069:Cell Respiration; D004734:Energy Metabolism; D005247:Feeding Behavior; D008099:Liver / Q000378:metabolism*; D008297:Male; D051379:Mice / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D008928:Mitochondria / Q000378:metabolism*; D008954:Models, Biological; D009929:Organ Size; D012044:Regression Analysis; D012641:Selection, Genetic; D015430:Weight Gain