The production of prostaglandins E and F of the 1-, 2- and 3-series was determined in primary cultures of turbot (Scophthalmus maximus) brain astroglial cells after supplementation with 25 microM dihomo-gamma-linolenic (20:3(n-6)), arachidonic (20:4(n-6)) and eicosapentaenoic (20:5(n-3)) acids. Supplementation by 20:3(n-6), 20:4(n-6) and 20:5(n-3) for 4 days significantly increased the percentages of the respective acids in the total cellular lipid of the turbot astrocytes. The predominant prostaglandins formed by turbot astrocytes in response to stimulation with calcium ionophore A23187 were prostaglandin E2 and prostaglandin F2 alpha under all experimental conditions. The production of prostaglandin E2 was stimulated 2.6-fold, but prostaglandin F2 alpha production was unaffected after supplementation of cultures with 20:4(n-6). However, prostaglandin E2 production in astrocytes was significantly inhibited 3- and 4-fold, and prostaglandin F2 alpha was inhibited 1.6- and 14.6-fold by supplementation with 20:3(n-6) and 20:5(n-3), respectively. Supplementation with 20:3(n-6) also significantly increased the production of prostaglandin E1 (almost 4-fold) and prostaglandin F1 alpha (2.2-fold) whereas supplementation with 20:5(n-3) did not significantly increase the production of prostaglandin E3. Prostaglandin F3 alpha but not prostaglandin E1 were significantly reduced in 20:5(n-3)-supplemented cultures.