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Metabolic challenges reveal impaired fatty acid metabolism and translocation of FAT/CD36 but not FABPpm in obese Zucker rat muscle.
Am J Physiol Endocrinol Metab 2007; 293(2):E566-75AJ

Abstract

We examined, in muscle of lean and obese Zucker rats, basal, insulin-induced, and contraction-induced fatty acid transporter translocation and fatty acid uptake, esterification, and oxidation. In lean rats, insulin and contraction induced the translocation of the fatty acid transporter FAT/CD36 (43 and 41%, respectively) and plasma membrane-associated fatty acid binding protein (FABPpm; 19 and 60%) and increased fatty acid uptake (63 and 40%, respectively). Insulin and contraction increased lean muscle palmitate esterification and oxidation 72 and 61%, respectively. In obese rat muscle, basal levels of sarcolemmal FAT/CD36 (+33%) and FABPpm (+14%) and fatty acid uptake (+30%) and esterification (+32%) were increased, whereas fatty acid oxidation was reduced (-28%). Insulin stimulation of obese rat muscle increased plasmalemmal FABPpm (+15%) but not plasmalemmal FAT/CD36, blunted fatty acid uptake and esterification, and failed to reduce fatty acid oxidation. In contracting obese rat muscle, the increases in fatty acid uptake and esterification and FABPpm translocation were normal, but FAT/CD36 translocation was impaired and fatty acid oxidation was blunted. There was no relationship between plasmalemmal fatty acid transporters and palmitate partitioning. In conclusion, fatty acid metabolism is impaired at several levels in muscles of obese Zucker rats; specifically, they are 1) insulin resistant with respect to FAT/CD36 translocation and fatty acid uptake, esterification, and oxidation and 2) contraction resistant with respect to fatty acid oxidation and FAT/CD36 translocation, but, conversely, 3) obese muscles are neither insulin nor contraction resistant at the level of FABPpm. Finally, 4) there is no evidence that plasmalemmal fatty acid transporters contribute to the channeling of fatty acids to specific metabolic destinations within the muscle.

Authors+Show Affiliations

Dept. of Human Health and Nutritional Sciences, Univ. of Guelph, Guelph, Ontario, Canada N1G 2W1.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

17519284

Citation

Han, Xiao-Xia, et al. "Metabolic Challenges Reveal Impaired Fatty Acid Metabolism and Translocation of FAT/CD36 but Not FABPpm in Obese Zucker Rat Muscle." American Journal of Physiology. Endocrinology and Metabolism, vol. 293, no. 2, 2007, pp. E566-75.
Han XX, Chabowski A, Tandon NN, et al. Metabolic challenges reveal impaired fatty acid metabolism and translocation of FAT/CD36 but not FABPpm in obese Zucker rat muscle. Am J Physiol Endocrinol Metab. 2007;293(2):E566-75.
Han, X. X., Chabowski, A., Tandon, N. N., Calles-Escandon, J., Glatz, J. F., Luiken, J. J., & Bonen, A. (2007). Metabolic challenges reveal impaired fatty acid metabolism and translocation of FAT/CD36 but not FABPpm in obese Zucker rat muscle. American Journal of Physiology. Endocrinology and Metabolism, 293(2), pp. E566-75.
Han XX, et al. Metabolic Challenges Reveal Impaired Fatty Acid Metabolism and Translocation of FAT/CD36 but Not FABPpm in Obese Zucker Rat Muscle. Am J Physiol Endocrinol Metab. 2007;293(2):E566-75. PubMed PMID: 17519284.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Metabolic challenges reveal impaired fatty acid metabolism and translocation of FAT/CD36 but not FABPpm in obese Zucker rat muscle. AU - Han,Xiao-Xia, AU - Chabowski,Adrian, AU - Tandon,Narendra N, AU - Calles-Escandon,Jorge, AU - Glatz,Jan F C, AU - Luiken,Joost J F P, AU - Bonen,Arend, Y1 - 2007/05/22/ PY - 2007/5/24/pubmed PY - 2007/9/25/medline PY - 2007/5/24/entrez SP - E566 EP - 75 JF - American journal of physiology. Endocrinology and metabolism JO - Am. J. Physiol. Endocrinol. Metab. VL - 293 IS - 2 N2 - We examined, in muscle of lean and obese Zucker rats, basal, insulin-induced, and contraction-induced fatty acid transporter translocation and fatty acid uptake, esterification, and oxidation. In lean rats, insulin and contraction induced the translocation of the fatty acid transporter FAT/CD36 (43 and 41%, respectively) and plasma membrane-associated fatty acid binding protein (FABPpm; 19 and 60%) and increased fatty acid uptake (63 and 40%, respectively). Insulin and contraction increased lean muscle palmitate esterification and oxidation 72 and 61%, respectively. In obese rat muscle, basal levels of sarcolemmal FAT/CD36 (+33%) and FABPpm (+14%) and fatty acid uptake (+30%) and esterification (+32%) were increased, whereas fatty acid oxidation was reduced (-28%). Insulin stimulation of obese rat muscle increased plasmalemmal FABPpm (+15%) but not plasmalemmal FAT/CD36, blunted fatty acid uptake and esterification, and failed to reduce fatty acid oxidation. In contracting obese rat muscle, the increases in fatty acid uptake and esterification and FABPpm translocation were normal, but FAT/CD36 translocation was impaired and fatty acid oxidation was blunted. There was no relationship between plasmalemmal fatty acid transporters and palmitate partitioning. In conclusion, fatty acid metabolism is impaired at several levels in muscles of obese Zucker rats; specifically, they are 1) insulin resistant with respect to FAT/CD36 translocation and fatty acid uptake, esterification, and oxidation and 2) contraction resistant with respect to fatty acid oxidation and FAT/CD36 translocation, but, conversely, 3) obese muscles are neither insulin nor contraction resistant at the level of FABPpm. Finally, 4) there is no evidence that plasmalemmal fatty acid transporters contribute to the channeling of fatty acids to specific metabolic destinations within the muscle. SN - 0193-1849 UR - https://www.unboundmedicine.com/medline/citation/17519284/Metabolic_challenges_reveal_impaired_fatty_acid_metabolism_and_translocation_of_FAT/CD36_but_not_FABPpm_in_obese_Zucker_rat_muscle_ L2 - http://www.physiology.org/doi/full/10.1152/ajpendo.00106.2007?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -