We examined effects of interleukin 1α (IL-1α) on prostaglandin production in piglet cultured astroglia. Immunoand morphologically identified polymorphic and process-bearing astrocytes were collected from cerebral cortex and white matter from piglets (1-3 days of age). Levels of prostaglandins were determined using enzyme immunoassay. Baseline levels for prostaglandin (PG) F 2 α were 631 ± 332 pg/ml and increased to 1417 ± 353 pg/ml 20 min after addition of 11 μg/ml IL-1α (p < 0.05) and to 2280 ± 391 pg/ml 20 min after addition of 22 μg/ml IL-1α (p < 0.05) (n = 7). Only small amounts of 6-keto-PGF 1 α or PGE 2 α were detected in medium under baseline conditions or in the presence of IL-1α. Medium alone did not change PGF 2 α levels (n = 3). Coapplication of cycloheximide (10 - 3 M) blocked the increase in PGF 2 α (n = 3). We conclude that IL-1α causes a rapid increase in prostaglandin production by astroglia, and this process involves a step requiring continued or increased protein synthesis.