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Vitamin A deficiency reduces liver and colon docosahexaenoic acid levels in rats fed high linoleic and low alpha-linolenic acid diet.

Abstract

Studies indicate that the transcription factor peroxisome proliferator-activated receptors (PPARs) regulate the activity of delta-6 and -5 desaturases and several key enzymes of peroxisomal beta-oxidation, including acyl-CoA oxidase. These enzymes are vital for the synthesis of docosahexaenoic (22:6 omega 3; DHA) and osbond (22:5 omega 6, OA) acids. An activated PPAR must form a hetrodimer with the obligate cofactor retinoid X receptor (RXR) to interact with a peroxisome proliferator responsive element (PPRE) of a target gene and to regulate transcriptional expression. The vitamin A metabolite, 9-cis retinoic acid, is the most potent ligand of RXR. We have tested the possibility that deficiency of vitamin A would compromise tissue levels of both DHA and OA in rats. Two groups of male Wistar rats were randomly distributed to receive vitamin A deficient (VAD) or sufficient (VAS) diet. After seven weeks of feeding, the rats were killed and colon and liver tissues removed for the analysis of fatty acids and antioxidant status. The VAD compared to the VAS rats had elevated levels of arachidonic (AA, P<0.001), adrenic acid (22:4 omega 6, P<0.005) and OA (P<0.0001) and reduced proportions of eicosapentaenoic (EPA, docosapentaenoic (DPA), DHA and total omega 3 fatty (P<0.0001) in colon choline phosphoglycerides (CPG). Similarly, liver CPG of the VAD rats had higher AA and adrenic acid and OA (P<0.0001), and lower EPA, DPA and DHA (P<0.0001) than the VAS rats. There was a similar fatty acid pattern in ethanolamine phosphoglycerides of the colon and liver tissues. These differences could not be explained by the conventional microsomal-peroxisomal pathway of the synthesis of the long-chain omega 6 and omega 3 polyunsaturated fatty acids. We postulate that deficiency of dietary vitamin A and the consequential depletion of retinoids inhibits DHA, and enhances OA, synthesis by differential effects on the independent synthetic pathways of the two fatty acids in the mitochondria. Various studies have documented that both DHA and vitamin A are vital for optimal visual and neural development and function. There is a need for further investigations to elucidate how vitamin A deficiency reduces membrane DHA level, and to delineate the synergistic effect of the two nutrients on vision, learning and memory.

Authors+Show Affiliations

Institute of Brain Chemistry and Human Nutrition, London Metropolitan University, 166-220 Holloway Road, London N7 8DB, UK. dez002@unl.ac.ukNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15519497

Citation

Zhou, D, et al. "Vitamin a Deficiency Reduces Liver and Colon Docosahexaenoic Acid Levels in Rats Fed High Linoleic and Low Alpha-linolenic Acid Diet." Prostaglandins, Leukotrienes, and Essential Fatty Acids, vol. 71, no. 6, 2004, pp. 383-9.
Zhou D, Zaiger G, Ghebremeskel K, et al. Vitamin A deficiency reduces liver and colon docosahexaenoic acid levels in rats fed high linoleic and low alpha-linolenic acid diet. Prostaglandins Leukot Essent Fatty Acids. 2004;71(6):383-9.
Zhou, D., Zaiger, G., Ghebremeskel, K., Crawford, M. A., & Reifen, R. (2004). Vitamin A deficiency reduces liver and colon docosahexaenoic acid levels in rats fed high linoleic and low alpha-linolenic acid diet. Prostaglandins, Leukotrienes, and Essential Fatty Acids, 71(6), 383-9.
Zhou D, et al. Vitamin a Deficiency Reduces Liver and Colon Docosahexaenoic Acid Levels in Rats Fed High Linoleic and Low Alpha-linolenic Acid Diet. Prostaglandins Leukot Essent Fatty Acids. 2004;71(6):383-9. PubMed PMID: 15519497.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Vitamin A deficiency reduces liver and colon docosahexaenoic acid levels in rats fed high linoleic and low alpha-linolenic acid diet. AU - Zhou,D, AU - Zaiger,G, AU - Ghebremeskel,K, AU - Crawford,M A, AU - Reifen,R, PY - 2004/05/12/received PY - 2004/07/29/accepted PY - 2004/11/3/pubmed PY - 2005/4/22/medline PY - 2004/11/3/entrez SP - 383 EP - 9 JF - Prostaglandins, leukotrienes, and essential fatty acids JO - Prostaglandins Leukot Essent Fatty Acids VL - 71 IS - 6 N2 - Studies indicate that the transcription factor peroxisome proliferator-activated receptors (PPARs) regulate the activity of delta-6 and -5 desaturases and several key enzymes of peroxisomal beta-oxidation, including acyl-CoA oxidase. These enzymes are vital for the synthesis of docosahexaenoic (22:6 omega 3; DHA) and osbond (22:5 omega 6, OA) acids. An activated PPAR must form a hetrodimer with the obligate cofactor retinoid X receptor (RXR) to interact with a peroxisome proliferator responsive element (PPRE) of a target gene and to regulate transcriptional expression. The vitamin A metabolite, 9-cis retinoic acid, is the most potent ligand of RXR. We have tested the possibility that deficiency of vitamin A would compromise tissue levels of both DHA and OA in rats. Two groups of male Wistar rats were randomly distributed to receive vitamin A deficient (VAD) or sufficient (VAS) diet. After seven weeks of feeding, the rats were killed and colon and liver tissues removed for the analysis of fatty acids and antioxidant status. The VAD compared to the VAS rats had elevated levels of arachidonic (AA, P<0.001), adrenic acid (22:4 omega 6, P<0.005) and OA (P<0.0001) and reduced proportions of eicosapentaenoic (EPA, docosapentaenoic (DPA), DHA and total omega 3 fatty (P<0.0001) in colon choline phosphoglycerides (CPG). Similarly, liver CPG of the VAD rats had higher AA and adrenic acid and OA (P<0.0001), and lower EPA, DPA and DHA (P<0.0001) than the VAS rats. There was a similar fatty acid pattern in ethanolamine phosphoglycerides of the colon and liver tissues. These differences could not be explained by the conventional microsomal-peroxisomal pathway of the synthesis of the long-chain omega 6 and omega 3 polyunsaturated fatty acids. We postulate that deficiency of dietary vitamin A and the consequential depletion of retinoids inhibits DHA, and enhances OA, synthesis by differential effects on the independent synthetic pathways of the two fatty acids in the mitochondria. Various studies have documented that both DHA and vitamin A are vital for optimal visual and neural development and function. There is a need for further investigations to elucidate how vitamin A deficiency reduces membrane DHA level, and to delineate the synergistic effect of the two nutrients on vision, learning and memory. SN - 0952-3278 UR - https://www.unboundmedicine.com/medline/citation/15519497/Vitamin_A_deficiency_reduces_liver_and_colon_docosahexaenoic_acid_levels_in_rats_fed_high_linoleic_and_low_alpha_linolenic_acid_diet_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0952-3278(04)00134-6 DB - PRIME DP - Unbound Medicine ER -