In:
Biochemical Journal, Portland Press Ltd., Vol. 249, No. 3 ( 1988-02-01), p. 801-806
Abstract:
Fatty acid oxidation and synthesis were studied in isolated hepatocytes from adult rats adapted for 44 days on low-fat, high-carbohydrate (LF), diet or high-fat diets, composed of long-chain (LCT) or medium-chain (MCT) triacylglycerols. The rates of [1-14C]octanoate oxidation were almost similar in each group studied, whereas the oxidation of [1-14C] oleate was 50% lower in the LF group than in animals adapted to high-fat diets. The rates of oleate oxidation are inversely correlated with the rates of lipogenesis. However, it seems unlikely that [malonyl-CoA] itself represents the sole mechanism involved in the regulation of oleate oxidation during long-term LCT or MCT feeding, since: (1) despite a 3-fold higher concentration of malonyl-CoA in MCT-fed rats than in LCT-fed ones, the rates of oleate oxidation are similar; (2) when malonyl-CoA concentration is increased after stimulation of lipogenesis (by adding lactate + pyruvate) in MCT-fed rats, to a level comparable with that of the LF group, the rate of oleate oxidation remains 55% higher than that measured under similar conditions in the LF-fed rats; (3) in the LF group, the 90% decrease in malonyl-CoA concentration [by 5-(tetradecyloxy)-2-furoic acid] is not associated with a stimulation of oleate oxidation. By contrast, the sensitivity of carnitine palmitoyltransferase I (CPT I) to malonyl-CoA is markedly decreased in the LCT- and MCT-fed rats, by 90% and 70% respectively. The relevance of this decrease in the sensitivity of CPT I is discussed.
Type of Medium:
Online Resource
ISSN:
0264-6021
,
1470-8728
Language:
English
Publisher:
Portland Press Ltd.
Publication Date:
1988
detail.hit.zdb_id:
1473095-9
SSG:
12
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