Journal
NUTRITION
Volume 25, Issue 7-8, Pages 828-838Publisher
ELSEVIER SCIENCE INC
DOI: 10.1016/j.nut.2009.01.008
Keywords
Vitamin A; Fatty acid oxidation; Peroxisome proliferator-activated receptors; Carnitine palmitoyltransferase; Retinoic X receptors; Acetyl-coenzyme A carboxylase; Mitochondria
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Funding
- National Investigations Council of Science and Technology
- Secretary of Science and Technology of San Luis University
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Objective: We studied the effect of dietary vitamin A deprivation on lipid composition and mRNA expression of regulatory enzymes involved in rat heart energetic lipid metabolism and its relation to the expression of peroxisome proliferator-activated receptor (PPAR) and retinoid X receptor (RXR) genes. Methods: Male Wistar 21-d-old rats were fed for 3 mo with a vitamin A-free diet (vitamin A-deficient group) and the same diet plus 8 mg of retinol palmitate per kilogram of diet (control group). One group of deficient animals received the control diet 15 d before sacrifice (vitamin A-refed group). Heart ventricular and mitochondrial lipid contents were determined. Lipid synthesis was measured using radioactive precursors and acetyl-coenzyme A carboxylase and mitochondrial carnitine palmitoyltransferase-1 (CPT-1) activities using radioactive substrates. Fatty acid composition of mitochondrial phospholipids was analyzed by gas-liquid chromatography. Heart expression of acetyl-coenzyme A carboxylase, CPT-1, PPAR-alpha, PPAR-beta, RXR-alpha, and RXR-beta was assessed by reverse transcriptase polymerase chain reaction, and CPT-I expression was also measured by real-time polymerase chain reaction. Results: Vitamin A deficiency induced changes in heart ventricular lipid content and synthesis. Mitochondrial cardiolipin decreased and the proportion of phospholipids/saturated fatty acids increased. Heart activity and mRNA levels of CPT-I and expression of PPAR-alpha and PPAR-beta genes were enhanced, whereas acetyl-coenzyme A carboxylase activity diminished. Furthermore, vitamin A deficiency decreased heart mRNA levels of RXRs. Vitamin A refeeding reverted most of the observed changes. Conclusion: Lipid metabolism is significantly modified in hearts of vitamin A-deficient rats. Alteration of mitochondrial energetic processes by modifying the activity and gene expressions of the regulatory enzymes is associated with a high PPAR expression induced by vitamin A deprivation. (C) 2009 Published by Elsevier Inc.
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