DIETARY MODULATION OF FATTY-ACID COMPOSITION OF MAST-CELL PHOSPHOLIPIDS DOES NOT AFFECT HISTAMINE-RELEASE INDUCED BY COMPOUND-48 80/

Objective and Design: In the present study we determined the extent to which the degranulation process in mast cells was related to the fatt y acid composition of membrane phospholipids. Material: Peritoneal mas t cells were isolated from Wistar rats (3 groups of 18 animals each), fed for 6 weeks diets which differed in their fatty acid compositions: (i) genuine salmon oil, abundant in (n-3) fatty acids, (ii) sunflower seed oil, rich in (n-6) fatty acids, particularly linoleic acid, and ( iii) hydrogenated coconut oil, rich in saturated fatty acids. Methods: Mast cells (10(6)/ml) were stimulated with various concentrations of the mast cell-degranulating agent, compound 48/80 (0.1-10 mu g/ml). Th e extent of mast cell degranulation was quantified by determination of histamine in the supernatants using HPLC techniques. Results: No diff erences in compound 48/80-induced histamine release between the three dietary groups for any of the concentrations of compound 48/80 tested were found. Analysis of variance followed by Tukey's method for multip le comparisons was used to evaluate the effect of changes in the dieta ry fat type. Conclusion: These findings strongly suggest that in contr ast to the formation of eicosanoids, the process of mast cell degranul ation by a receptor-independent pathway is not controlled by the fatty acid composition of membrane phospholipids.