Dataset Information

Fatty acid metabolism in hepatocytes isolated from rats adapted to high-fat diets containing long- or medium-chain triacylglycerols.

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.

SUBMITTER: Pegorier JP

PROVIDER: S-EPMC1148777 | biostudies-other | 1988 Feb

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:BackgroundDiets containing fats of different proportions and types have been demonstrated to influence metabolism. These fats differ in long chain fatty acids (LCFAs) or medium chain fatty acids (MCFAs) content. In our laboratory using swimming as the training modality, MCFAs increased endurance attributed to increased activities of oxidative enzymes. How it affects whole-body metabolism remains unexplored. The present study investigated the metabolic, biochemical and genetic adaptations with treadmill running as the training modality.MethodsC57BL/6N mice were divided into untrained and trained groups and provided with low-fat (10% kcal from soybean oil), coconut oil (10% kcal from soybean oil, 20% kcal from coconut oil) or soybean oil (30% kcal from soybean oil) diet. Training was performed on a treadmill for 30 days. After recovery, whole-body metabolism at rest and during exercise, endurance, substrate metabolism, mitochondrial enzyme activities, and gene expression of training-adaptive genes in the muscle and liver were measured.ResultsAt rest, medium-fat diets decreased respiratory exchange ratio (RER) (p < 0.05). Training increased RER in all diet groups without affecting oxygen consumption (p < 0.05). During exercise, diets had no overt effects on metabolism while training decreased oxygen consumption indicating decreased energy expenditure (p < 0.05). Coconut oil without training improved endurance based on work (p < 0.05). Training improved all endurance parameters without overt effects of diet (p < 0.05). Moreover, training increased the activities of mitochondrial enzymes likely related to the increased expression of estrogen related receptor (ERR) α and ERRβ (p < 0.05). Coconut oil inhibited peroxisome proliferator-activated receptor (PPAR) β/δ activation and glycogen accumulation in the muscle but activated PPARα in the liver in the trained state (p < 0.05). Substrate utilization data suggested that coconut oil and/or resulting ketone bodies spared glycogen utilization in the trained muscle during exercise thereby preserving endurance.ConclusionOur data demonstrated the various roles of diet and fat types in training adaptation. Diets exerted different roles in PPAR activation and substrate handling in the context of endurance exercise training. However, the role of fat types in training adaptations is limited as training overwhelms and normalizes the effects of diet in the untrained state particularly on endurance performance, mitochondrial biogenesis, and ERR expression.

Dataset Information

Fatty acid metabolism in hepatocytes isolated from rats adapted to high-fat diets containing long- or medium-chain triacylglycerols.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets