Catch-up growth - a risk for later obesity and type 2 diabetes - is characterized by a higher rate of fat relative to lean tissue deposition. Using a rat model of refeeding after semistarvation, such catch-up fat has been shown to be primarily driven by suppressed thermogenesis and to be exacerbated by high-fat diets rich in animal (saturated) fats. This latter exacerbation of catch-up fat is however not observed with safflower oil - which is rich in omega-6 polyunsaturated fatty acids; these anti-obesity effects being explained partly by a higher lean tissue deposition and partly by enhanced thermogenesis. We investigated here the role of altered liver mitochondrial energy coupling and relative oxidative stress (assessed as SOD specific activity) in such dietary modulation of catch-up fat. After 14 days of semistarvation, male Sprague-Dawley rats were refed for 7 days with isocaloric amounts of either a low-fat diet, a high-fat lard diet or high-fat safflower oil diet. Compared to the group refed the high-fat lard diet, the rats refed isocalorically on high-fat safflower oil diet gained less body fat but more body protein, and their isolated liver mitochondria showed increased proton leak (basal and palmitate-induced) and decreased oxidative stress. Thus the exaggerated suppression of thermogenesis that exacerbates catch-up fat on high-fat diets is counteracted by a diet rich in omega-6 fatty acids, in part by a shift in energy partitioning from body fat to protein, and in part via increased thermogenesis resulting from increased hepatic mitochondrial proton leak and decreased mitochodrial efficiency.
OMEGA-6-FATTY ACIDS RICH DIETS DECREASE LIVER MITOCHONDRIAL EFFICIENCY DURING REFEEDING AFTER CALORIC RESTRICTION IN RAT / Crescenzo, Raffaella; Bianco, F.; Falcone, Italia; Yepuri, G.; Dulloo, A. G.; Liverini, Giovanna; Iossa, Susanna. - In: INTERNATIONAL JOURNAL OF OBESITY. - ISSN 0307-0565. - STAMPA. - 32:(2008), pp. 162-162. (Intervento presentato al convegno 16 TH EUROPEAN CONGRESS ON OBESITY tenutosi a GENEVA, SWITZERLND nel 14-17 MAY 2008).
OMEGA-6-FATTY ACIDS RICH DIETS DECREASE LIVER MITOCHONDRIAL EFFICIENCY DURING REFEEDING AFTER CALORIC RESTRICTION IN RAT.
CRESCENZO, RAFFAELLA;FALCONE, ITALIA;LIVERINI, GIOVANNA;IOSSA, SUSANNA
2008
Abstract
Catch-up growth - a risk for later obesity and type 2 diabetes - is characterized by a higher rate of fat relative to lean tissue deposition. Using a rat model of refeeding after semistarvation, such catch-up fat has been shown to be primarily driven by suppressed thermogenesis and to be exacerbated by high-fat diets rich in animal (saturated) fats. This latter exacerbation of catch-up fat is however not observed with safflower oil - which is rich in omega-6 polyunsaturated fatty acids; these anti-obesity effects being explained partly by a higher lean tissue deposition and partly by enhanced thermogenesis. We investigated here the role of altered liver mitochondrial energy coupling and relative oxidative stress (assessed as SOD specific activity) in such dietary modulation of catch-up fat. After 14 days of semistarvation, male Sprague-Dawley rats were refed for 7 days with isocaloric amounts of either a low-fat diet, a high-fat lard diet or high-fat safflower oil diet. Compared to the group refed the high-fat lard diet, the rats refed isocalorically on high-fat safflower oil diet gained less body fat but more body protein, and their isolated liver mitochondria showed increased proton leak (basal and palmitate-induced) and decreased oxidative stress. Thus the exaggerated suppression of thermogenesis that exacerbates catch-up fat on high-fat diets is counteracted by a diet rich in omega-6 fatty acids, in part by a shift in energy partitioning from body fat to protein, and in part via increased thermogenesis resulting from increased hepatic mitochondrial proton leak and decreased mitochodrial efficiency.File | Dimensione | Formato | |
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