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In obese rat muscle transport of palmitate is increased and is channeled to triacylglycerol storage despite an increase in mitochondrial palmitate oxidation.
Am J Physiol Endocrinol Metab 2009; 296(4):E738-47AJ

Abstract

Intramuscular triacylglycerol (IMTG) accumulation in obesity has been attributed to increased fatty acid transport and/or to alterations in mitochondrial fatty acid oxidation. Alternatively, an imbalance in these two processes may channel fatty acids into storage. Therefore, in red and white muscles of lean and obese Zucker rats, we examined whether the increase in IMTG accumulation was attributable to an increased rate of fatty acid transport rather than alterations in subsarcolemmal (SS) or intermyofibrillar (IMF) mitochondrial fatty acid oxidation. In obese animals selected parameters were upregulated, including palmitate transport (red: +100%; white: +51%), plasmalemmal FAT/CD36 (red: +116%; white: +115%; not plasmalemmal FABPpm, FATP1, or FATP4), IMTG concentrations (red: approximately 2-fold; white: approximately 4-fold), and mitochondrial content (red +30%). Selected mitochondrial parameters were also greater in obese animals, namely, palmitate oxidation (SS red: +91%; SS white: +26%; not IMF mitochondria), FAT/CD36 (SS: +65%; IMF: +65%), citrate synthase (SS: +19%), and beta-hydroxyacyl-CoA dehydrogenase activities (SS: +20%); carnitine palmitoyltransferase-I activity did not differ. A comparison of lean and obese rat muscles revealed that the rate of change in IMTG concentration was eightfold greater than that of fatty acid oxidation (SS mitochondria), when both parameters were expressed relative to fatty transport. Thus fatty acid transport, esterification, and oxidation (SS mitochondria) are upregulated in muscles of obese Zucker rats, with these effects being most pronounced in red muscle. The additional fatty acid taken up is channeled primarily to esterification, suggesting that upregulation in fatty acid transport as opposed to altered fatty acid oxidation is the major determinant of intramuscular lipid accumulation.

Authors+Show Affiliations

Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, ON, Canada.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo 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

19141681

Citation

Holloway, Graham P., et al. "In Obese Rat Muscle Transport of Palmitate Is Increased and Is Channeled to Triacylglycerol Storage Despite an Increase in Mitochondrial Palmitate Oxidation." American Journal of Physiology. Endocrinology and Metabolism, vol. 296, no. 4, 2009, pp. E738-47.
Holloway GP, Benton CR, Mullen KL, et al. In obese rat muscle transport of palmitate is increased and is channeled to triacylglycerol storage despite an increase in mitochondrial palmitate oxidation. Am J Physiol Endocrinol Metab. 2009;296(4):E738-47.
Holloway, G. P., Benton, C. R., Mullen, K. L., Yoshida, Y., Snook, L. A., Han, X. X., ... Bonen, A. (2009). In obese rat muscle transport of palmitate is increased and is channeled to triacylglycerol storage despite an increase in mitochondrial palmitate oxidation. American Journal of Physiology. Endocrinology and Metabolism, 296(4), pp. E738-47. doi:10.1152/ajpendo.90896.2008.
Holloway GP, et al. In Obese Rat Muscle Transport of Palmitate Is Increased and Is Channeled to Triacylglycerol Storage Despite an Increase in Mitochondrial Palmitate Oxidation. Am J Physiol Endocrinol Metab. 2009;296(4):E738-47. PubMed PMID: 19141681.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - In obese rat muscle transport of palmitate is increased and is channeled to triacylglycerol storage despite an increase in mitochondrial palmitate oxidation. AU - Holloway,Graham P, AU - Benton,Carley R, AU - Mullen,Kerry L, AU - Yoshida,Yuko, AU - Snook,Laelie A, AU - Han,Xiao-Xia, AU - Glatz,Jan F C, AU - Luiken,Joost J F P, AU - Lally,James, AU - Dyck,David J, AU - Bonen,Arend, Y1 - 2009/01/13/ PY - 2009/1/15/entrez PY - 2009/1/15/pubmed PY - 2009/5/22/medline SP - E738 EP - 47 JF - American journal of physiology. Endocrinology and metabolism JO - Am. J. Physiol. Endocrinol. Metab. VL - 296 IS - 4 N2 - Intramuscular triacylglycerol (IMTG) accumulation in obesity has been attributed to increased fatty acid transport and/or to alterations in mitochondrial fatty acid oxidation. Alternatively, an imbalance in these two processes may channel fatty acids into storage. Therefore, in red and white muscles of lean and obese Zucker rats, we examined whether the increase in IMTG accumulation was attributable to an increased rate of fatty acid transport rather than alterations in subsarcolemmal (SS) or intermyofibrillar (IMF) mitochondrial fatty acid oxidation. In obese animals selected parameters were upregulated, including palmitate transport (red: +100%; white: +51%), plasmalemmal FAT/CD36 (red: +116%; white: +115%; not plasmalemmal FABPpm, FATP1, or FATP4), IMTG concentrations (red: approximately 2-fold; white: approximately 4-fold), and mitochondrial content (red +30%). Selected mitochondrial parameters were also greater in obese animals, namely, palmitate oxidation (SS red: +91%; SS white: +26%; not IMF mitochondria), FAT/CD36 (SS: +65%; IMF: +65%), citrate synthase (SS: +19%), and beta-hydroxyacyl-CoA dehydrogenase activities (SS: +20%); carnitine palmitoyltransferase-I activity did not differ. A comparison of lean and obese rat muscles revealed that the rate of change in IMTG concentration was eightfold greater than that of fatty acid oxidation (SS mitochondria), when both parameters were expressed relative to fatty transport. Thus fatty acid transport, esterification, and oxidation (SS mitochondria) are upregulated in muscles of obese Zucker rats, with these effects being most pronounced in red muscle. The additional fatty acid taken up is channeled primarily to esterification, suggesting that upregulation in fatty acid transport as opposed to altered fatty acid oxidation is the major determinant of intramuscular lipid accumulation. SN - 0193-1849 UR - https://www.unboundmedicine.com/medline/citation/19141681/In_obese_rat_muscle_transport_of_palmitate_is_increased_and_is_channeled_to_triacylglycerol_storage_despite_an_increase_in_mitochondrial_palmitate_oxidation_ L2 - http://www.physiology.org/doi/full/10.1152/ajpendo.90896.2008?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -