title: Effect of the delta6-desaturase inhibitor SC-26196 on PUFA metabolism in human cells.
abstract: The objective of this study was to determine the effect of 2,2-diphenyl-5-(4-[[(1 E)-pyridin-3-yl-methylidene]amino]piperazin-1-yl)pentanenitrile (SC-26196), a delta6-desaturase inhibitor, on PUFA metabolism in human cells. SC-26196 inhibited the desaturation of 2 microM [1-14C] 18:2n-6 by 87-95% in cultured human skin fibroblasts, coronary artery smooth muscle cells, and astrocytes. By contrast, SC-26196 did not affect the conversion of [1-14C]20:3n-6 to 20:4 in the fibroblasts, demonstrating that it is selective for delta6-desaturase. The IC50 values for inhibition of the desaturation of 2 microM [1-14C] 18:3n-3 and [3-14C]24:5n-3 in the fibroblasts, 0.2-0.4 microM, were similar to those for the inhibition of [1-14C 18:2n-6 desaturation, and the rates of recovery of [1-14C]18:2n-6 and [3-14C]24:5n-3 desaturation after removal of SC-26196 from the culture medium also were similar. SC-26196 reduced the conversion of [3-14C]22:5n-3 and [3-14C]24:5n-3 to DHA by 75 and 84%, respectively, but it had no effect on the retroconversion of [3-14C]24:6n-3 to DHA. These results demonstrate that SC-26196 effectively inhibits the desaturation of 18- and 24-carbon PUFA and, therefore, decreases the synthesis of arachidonic acid, EPA, and DHA in human cells. Furthermore, they provide additional evidence that the conversion of 22:5n-3 to DHA involves delta6-desaturation.
authors.affiliation: Departmentof Biochemistry , University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Shawn D
authors.initials: SD
authors.lastname: Harmon
authors.forename: Terry L
authors.initials: TL
authors.lastname: Kaduce
authors.forename: Tony D
authors.initials: TD
authors.lastname: Manuel
authors.forename: Arthur A
authors.initials: AA
authors.lastname: Spector
mesh_terms: D002250:Carbon Radioisotopes; D002460:Cell Line; D004281:Docosahexaenoic Acids / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D044943:Fatty Acid Desaturases; D005231:Fatty Acids, Unsaturated / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D019787:Linoleic Acid / Q000737:chemistry / Q000378:metabolism; D010879:Piperazines / Q000494:pharmacology*; D013230:Stearoyl-CoA Desaturase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013997:Time Factors
chemical_list: D002250:Carbon Radioisotopes; D004791:Enzyme Inhibitors; D005231:Fatty Acids, Unsaturated; D010879:Piperazines; C120986:SC 26196; D004281:Docosahexaenoic Acids; C099831:tetracosahexaenoic acid; C099830:tetracosapentaenoic acid; D019787:Linoleic Acid; D044943:Fatty Acid Desaturases; D013230:Stearoyl-CoA Desaturase; C533241:FADS2 protein, human; C026219:docosapentaenoic acid