Effect of fatty acids of omega 6 series on the biosynthesis of arachidonic acid in HTC cells.

The influence of the preincubation of HTC cells with fatty acids of omega 6 series and columbinic acid (5t, 9c, 12c 18:3) on the biosynthesis of arachidonic acid was studied. The cells were incubated on a chemically defined medium with or without the addition of unlabeled linoleic, gamma-linolenic, eicosatrienoic, arachidonic, docosatetraenoic, docosapentaenoic and columbinic acids. After 24 hr of preincubation in the presence of the aforementioned fatty acids, [1-14C]eicosa-8,11,14-trienoic acid was added to the culture medium as the only lipidic source. Twenty-four hours later the synthesis of arachidonic acid and the fatty acid composition of the cells were determined. At 20 microM concentration the omega 6 fatty acids studied except docosapentaenoic acid produced an increase on the biosynthesis of arachidonic acid compared to the cells incubated in the absence of unlabeled fatty acids in the medium. The fatty acids added to the culture medium were incorporated into the cells and modified their fatty acid composition. Columbinic acid, with a similar structure to linoleic acid, also produced a significant increase on the conversion of eicosatrienoic acid to arachidonic acid. These results would suggest that the effect of both, linoleic and columbinic acids, may be adscribed to their configuration and not necessarily to their transformation in higher homologs, since columbinic acid is unable to be desaturated.