title: Oxidative metabolism: glucose versus ketones.
abstract: The coupling of upstream oxidative processes (glycolysis, beta-oxidation, CAC turnover) to mitochondrial oxidative phosphorylation (OXPHOS) under the driving conditions of energy demand by the cell results in the liberation of free energy as ATP. Perturbations in glycolytic CAC or OXPHOS can result in pathology or cell death. To better understand whole body energy expenditure during chronic ketosis, we used a diet-induced rat model of ketosis to determine if high-fat-carbohydrate-restricted "ketogenic" diet results in changes in total energy expenditure (TEE). Consistent with previous reports of increased energy expenditure in mice, we hypothesized that rats fed ketogenic diet for 3 weeks would result in increased resting energy expenditure due to alterations in metabolism associated with a "switch" in energy substrate from glucose to ketone bodies. The rationale is ketone bodies are a more efficient fuel than glucose. Indirect calorimetric analysis revealed a moderate increase in VO2 and decreased VCO2 and heat with ketosis. These results suggest ketosis induces a moderate uncoupling state and less oxidative efficiency compared to glucose oxidation.
authors.affiliation: Departments of Nutrition, Schools of Medicine and Engineering, Case Western Reserve University, 10900 Euclid Ave., W-G48, Cleveland, OH, 44106-4954, USA.
authors.forename: Allison
authors.initials: A
authors.lastname: Prince
authors.affiliation: Departments of Biomedical Engineering, Schools of Medicine and Engineering, Case Western Reserve University, 10900 Euclid Ave., W-G48, Cleveland, OH, 44106-4954, USA.
authors.forename: Yifan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Departments of Nutrition, Schools of Medicine and Engineering, Case Western Reserve University, 10900 Euclid Ave., W-G48, Cleveland, OH, 44106-4954, USA.
authors.forename: Colleen
authors.initials: C
authors.lastname: Croniger
authors.affiliation: Departments of Nutrition, Schools of Medicine and Engineering, Case Western Reserve University, 10900 Euclid Ave., W-G48, Cleveland, OH, 44106-4954, USA. map10@case.edu.
authors.forename: Michelle
authors.initials: M
authors.lastname: Puchowicz
mesh_terms: D000818:Animals; D002153:Calorimetry, Indirect / Q000379:methods; D002245:Carbon Dioxide / Q000378:metabolism; D055423:Diet, Ketogenic; D005947:Glucose / Q000378:metabolism*; D007657:Ketone Bodies / Q000378:metabolism*; D007662:Ketosis / Q000378:metabolism; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D007657:Ketone Bodies; D002245:Carbon Dioxide; D005947:Glucose; D010100:Oxygen