caa a22 4500 465766366 CHVBK 20180323111915.0 cr unu---uuuuu 170327e19900401xx s 000 0 eng 10.1007/BF02535749 doi (NATIONALLICENCE)springer-10.1007/BF02535749 Chain elongation of polyunsaturated fatty acids by vascular endothelial cells: Studies with arachidonate analogues [Elektronische Daten] [Martha Garcia, Howard Sprecher, Miriam Rosenthal] This study has utilized radiolabeled analogues of arachidonic acid to study the substrate specificity of elongation of long-chain polyunsaturated fatty acids. Human umbilical vein endothelial cells were incubated for 2-72 hr in medium supplemented with 0.9-2.6 μM [14C]fatty acid, and cellular glycerolipids were analyzed by gas-liquid chromatography with radioactivity detection. Elongation of naturally occurring C20 polyunsaturated fatty acids occurred with eicosapentaenoate (20∶5(n−3))>Mead acid (20∶3(n−9))>arachidonate (20∶4(n−6)). Chain length markedly influenced the extent of elongation of 5,8,11,14-tetraenoates (18∶4>19∶4>20∶4>21∶4); effects of initial double bond position were also observed (6,9,12,15-20∶4>4,7,10,13-20∶4. Neither 5,8,14- nor 5,11,14-20∶3 was elongated to the extent of 5,8,11-20∶3. Differences between polyunsaturated fatty acids were observed both in the initial rates and in the maximal percentages of elongation, suggesting that the content of cellular C20 and C22 fatty acids may represent a balance between chain elongation and retroconversion. Umbilical vein endothelial cells do not exhibit significant desaturation of either 22∶4(n−6) or 22∶5(n−3). By contrast, incubation with 5,8,11,14-[14C]18∶4(n−4) resulted in formation of both [14C]20∶5(n−4) and [14C]22∶5(n−4). The respective time courses for the appearances of [14C]22∶5(n−4) and [14C]20∶5(n−5) suggests Δ6 desaturation of [14C]22∶4(n−4) rather than Δ4 desaturation of [14C]20∶4(n−4). American Oil Chemists' Society, 1990 Garcia Martha Department of Biochemistry, Eastern Virginia medical School, 23501, Norfolk, VA aut Sprecher Howard Department of Physiological Chemistry, The Ohio State University, 43210, Columbus, OH aut Rosenthal Miriam Department of Biochemistry, Eastern Virginia medical School, 23501, Norfolk, VA aut Lipids Springer-Verlag 25/4(1990-04-01), 211-215 0024-4201 25:4<211 1990 25 11745 https://doi.org/10.1007/BF02535749 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02535749 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Garcia Martha Department of Biochemistry, Eastern Virginia medical School, 23501, Norfolk, VA aut NATIONALLICENCE 700 1- Sprecher Howard Department of Physiological Chemistry, The Ohio State University, 43210, Columbus, OH aut NATIONALLICENCE 700 1- Rosenthal Miriam Department of Biochemistry, Eastern Virginia medical School, 23501, Norfolk, VA aut NATIONALLICENCE 773 0- Lipids Springer-Verlag 25/4(1990-04-01), 211-215 0024-4201 25:4<211 1990 25 11745 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer