Fatty acid double bond orientation alters interaction with L-cell fibroblasts |
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Authors: | Clayton E Heyliger Talat J Kheshgi Eric J Murphy Sean Myers-Payne Friedhelm Schroeder |
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Institution: | (1) Division of Pharmacology and Medical Chemistry, Department of Pharmacology & Cell Biophysics, University of Cincinnati Medical Center, 45267-0004 Cincinnati, OH;(2) Department of Physiology and Pharmacology, Texas A&M University, TVMC, 77843-4466 College Station, TX, USA |
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Abstract: | Relatively little is known of fatty acid specificity in cellular fatty acid uptake. In this study L-cells, a fibroblastic cell line with very low levels of endogenous cytosolic fatty acid binding protein, were used to examine the role of cis and trans unsaturation on fatty acid uptake. The fluorescent fatty acids, trans-parinaric acid and cis-parinaric acid, were used as analogs of straight-chain saturated, and kinked-chain unsaturated fatty acids, respectively, in order to evaluate the fatty acid specificity of the uptake system. Parinaric acid is poorly metabolizable; greater than 97% was unesterified while 3H-oleic acid was almost totally metabolized after 30 min uptake. Cis- and trans-parinaric acid uptake was saturable and dependent on the concentration of fatty acid. However, the initial rate and maximal amount of trans-parinaric acid taken up by the L-cells was greater than for cis-parinaric acid under the same conditions. The affinity of L-cell uptake for trans-parinaric acid (Km = 0.12 uM) was 35-fold higher than that for cis-parinaric acid (Km = 4.17 uM) . Based on competition studies with oleic and stearic acids, it was concluded that the cis- and trans-parinaric acid were taken up by the same L-cell fatty acid uptake system. The results suggest that the L-cell fatty acid uptake system has selectivity for straight chain rather than kinked chain unsaturated fatty acids.Abbreviations Cis-parinaric acid
9Z, 11E, 13E, 15Z-octatetraenoic acid
- trans-parinaric acid
9E, I IE, 13E, 15E-octatetraenoic acid
- EGTA
ethylene glycol-bis(beta-amlno-ethyl ether) N,N,N,N-tetratacetic acid
- BSA
bovine serum albumin
- PBS
phosphate buffered saline |
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Keywords: | L-cells oleic acid cis-parinaric acid trans-parinaric acid fatty acid transport fluorescence |
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