Exposure of airway smooth muscle (ASM) cells to the cytokine IL-1 results in an induction of PGE₂ synthesis that affects numerous cell functions. Current dogma posits induction of COX-2 protein as the critical, obligatory event in cytokine-induced PGE₂ production, although PGE₂ induction can be inhibited without a concomitant inhibition of COX-2. To explore other putative regulatory features we examined the role of PLA₂ and PGES enzymes in IL-1-induced PGE₂ production. Treatment of human ASM cultures with IL-1 caused a time-dependent induction of both cPLA₂ and mPGES similar to that observed for COX-2. Regulation of COX-2 and mPGES induction was similar, being significantly reduced by inhibition of p42/p44 or p38, whereas cPLA₂ induction was only minimally reduced by inhibition of p38 or PKC. COX-2 and mPGES induction was subject to feed-forward regulation by PKA whereas cPLA₂ induction was not. SB202474, an SB203580 analogue lacking the ability to inhibit p38 but capable of inhibiting IL-1-induced PGE₂ production, was effective in inhibiting mPGES but not COX-2 or cPLA₂ induction. These data suggest that although COX-2, cPLA2 and mPGES are all induced by IL- in human ASM cells, regulatory features of cPLA₂ are dissociated, whereas those of COX-2 and mPGES are primarily associated, with regulation of PGE₂ production. mPGES induction, and possibly cPLA₂ induction appear to cooperate with COX-2 to determine IL-1-mediated PGE₂ production in human ASM cells.