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Thrombin stimulates the release of arachidonate but not 8,11,14-eicosatrienoate from endothelial cell glycerolipids

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:7246504
Previous studies in their laboratory have shown that thrombin stimulates the release of arachidonate (20:4(n-6)) but not 22:4(n-6) from endothelial cell glycerolipids. The authors now report that thrombin also does not significantly stimulate the release of 8,11,14-(/sup 14/C)eicosatrienoate per se. Human umbilical vein endothelial cells were radiolabeled for 24 hr with 1.25 ..mu..M (/sup 14/C)20:3(n-6) or (/sup 14/C)20:4(n-6). When incubated for 10 min in buffered saline with 50 ..mu..M fat-free albumin and 1 U/ml thrombin, these cells released 4.1% and 7.6%, respectively, of the previously incorporated radioactivity. Analysis of released /sup 14/C-fatty acids by radio-gas chromatography indicated that the thrombin-stimulated release from cells prelabelled with (/sup 14/C)20:3(n-6) was essentially due to release of (/sup 14/C)arachidonate synthesized endogenously by desaturation of the (/sup 14/C)20:3(n-6). Expressed as a percentage of each /sup 14/C-fatty acyl present moiety in cellular glycerolipids of cells prelabelled with (/sup 14/C)20:3(n-6), release was 8.2% for arachidonate but only 0.63% for 20:3(n-6). Studies with other /sup 14/C-fatty acids indicate that 5,8,11-20:3 is released in response to thrombin (5-9%); 8,11,14,17-20:4 is not (<1%). These results suggest that a ..delta..5 double bond in the fatty acid is necessary for thrombin-stimulated release from endothelial cell glycerolipids.
Research Organization:
Eastern Virginia Medical School, Norfolk
OSTI ID:
7246504
Report Number(s):
CONF-8606151-
Conference Information:
Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
Country of Publication:
United States
Language:
English