Effect of high-fat feeding on metabolic efficiency and mitochondrial oxidative capacity in adult rats.
The changes in metabolic efficiency, body composition, and nutrient partitioning induced by high-fat feeding were evaluated in adult rats (90 d of age). The alterations in serum free triiodothyronine, insulin, and leptin levels, as well as in hepatic and skeletal muscle metabolism, were also assessed. Rats were fed either a low- or a high-fat diet for 2 weeks. Relative to the low-fat feeding, energy intake and expenditure, as well as body-energy gain, lipid gain, and energetic efficiency, were increased by the high-fat feeding. Increased serum leptin levels accompanied these variations. A positive correlation between serum leptin levels and percentage of body fat was found in the rats fed the low- or high-fat diet, with a significant divergence between the slope of the regression lines. Furthermore, a negative correlation between serum leptin level and energy intake was found in the rats fed the low-fat diet, while a positive correlation was found in the rats fed the high-fat diet. Finally, the high-fat feeding decreased the hepatic and skeletal muscle mitochondrial oxidative capacity. It is concluded that, in adult rats, a nutritional factor such as a high level of fat in the diet induces obesity, leptin resistance, and impairment of mitochondrial capacity, all phenomena typical of unrestrained aged rats.
Iossa
Susanna
S
Department of General and Environmental Physiology, University of Naples Federico II, Via Mezzocannone 8, 1-80134 Napoli, Italy.
Lionetti
Lillà
L
Mollica
Maria P
MP
Crescenzo
Raffaella
R
Botta
Monica
M
Barletta
Antonio
A
Liverini
Giovanna
G
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition / Q000502:physiology; D004041:Dietary Fats / Q000008:administration & dosage*; D004734:Energy Metabolism / Q000502:physiology; D005230:Fatty Acids, Nonesterified / Q000097:blood; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood; D008099:Liver / Q000378:metabolism; D008297:Male; D008928:Mitochondria / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism; D008931:Mitochondria, Muscle / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D010084:Oxidation-Reduction; D051381:Rats; D017208:Rats, Wistar; D014284:Triiodothyronine / Q000097:blood
D001786:Blood Glucose; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D020738:Leptin; D014284:Triiodothyronine