EFFECT OF ALPHA-LINOLENIC ACID ON THE METABOLISM OF OMEGA-3 AND OMEGA-6 POLYUNSATURATED FATTY-ACIDS AND HISTAMINE-RELEASE IN RBL-2H3 CELLS

We examined the effect of alpha-linolenic acid (18:3 (n-3)) pretreatme nt on the metabolism of omega-3 and omega-6 polyunsaturated fatty acid s and histamine content and release of RBL-2H3 cells. RBL-2H3 cells gr ew without reduction in number when incubated with subculture media fo r 3d and then placed again in serum-free medium with bovine serum albu min (BSA) and epidermal growth factor (EGF). Cholesterol pullulan (10 mu g/ml) emulsified alpha-linolenic acid (20 mu g/ml) was recommended as an additional form serum free medium. We determined the fatty acid composition in all neutral lipids, free fatty acids and all phospholip ids in alpha-linolenic acid-treated cells. In all cases the concentrat ion of alpha-linolenic acid and docosahexenoic acid (DHA, 22:6 (n-3)) was increased, while linolenic acid (18:2(n-6)) was slightly and arach idonic acid (20:4 (n-6)) was markedly decreased. Content of histamine in alpha-linolenic acid-treated cells was remarkably lower than that o f untreated cells. Accordingly, net histamine release stimulated by an tigen or A23187 was also markedly decreased in the alpha-linolenic aci d-treated cells, as was the percent histamine release stimulated by an tigen. Results from our in vitro experiment suggest that the anti-alle rgic effect of alpha-linolenic acid may be caused either by the decrea se in histamine content or by inhibition of the release of chemical me diator resulting from changes in the fatty acid composition.