POLYUNSATURATED THIA-FATTY-ACIDS AND OXA-FATTY-ACIDS - INCORPORATION INTO CELL-LIPIDS AND THEIR EFFECTS ON ARACHIDONIC ACID SYNTHESIS AND EICOSANOID SYNTHESIS

EPA, DHA, C15SCH2COOH (n-3), C15SCH2COOH (n-6) and C18SCH2COOH (n-3) a re extensively incorporated into phospholipids and triacylglycerol in rat hepatocytes after 24 h incubation with 80 mu M fatty acid/derivati ve. Only traces of polyunsaturated 3-oxa fatty acids (C15OCH2COOH, C18 OCH2COOH) were incorporated, C-15-S-butyric acid (n-3) is a stronger i nhibitor of Delta(6)-desaturase in rat liver-microsomes than C15SCH2CO OH (n-3). C-15-S-propionic acid (n-3), EPA and DHA. It inhibits Delta( 5)-desaturase in a similar manner to EPA and DHA. Arachidonic acid and C15SCH2COOH, (n-6) are better substrates for PGH-synthase than EPA an d C15SCH2COOH, (n-3), showing the inhibitory effect of the n-3 bond. T he n-3 polyunsaturated fatty acids, including the sulfur-substituted f atty acid derivatives. are poor substrates for PGH-synthase. However, they inactivate the PGH-synthase activity at least as efficiently as a rachidonic acid. C15SCH2COOH (n-3), C15S(CH2)(2)COOH (n-3) and C18SCH2 COOH (n-3) induce peroxisomal beta-oxidation more than EPA and DHA. (C ) 1997 Elsevier Science B.V.