Because several ovulation-associated phenomena bear resemblance to inflammatory events, it has been hypothesized that cytokines may play a role in this connection. Among the known cytokines, interleukin (IL)-1 has been extensively evaluated. There are two types of IL-1 (α and β), two receptor types (I and II), and a naturally occurring receptor antagonist Signal transduction of IL-1β involves, it only in part, hydrolysis of sphingomyelin to ceramide. Type I IL-1 receptor has been shown to mediate several cellular functions, but type II has not. Nevertheless, the two receptor types do not form a complex with each other and therefore do not participate in a single signal transduction pathway. The mammalian ovary possesses all the components of the IL-1 system in a highly compartmentalized arrangement Some of these components are regulated by gonadotropins. Recent studies on the direct effects of IL-1 in the rat ovary revealed a significant increase in prostaglandins E2 and F2α biosynthesis. In light of the above compartmentalized arrangement, it is interesting that both granulosa and theca cells are needed for prostaglandin production. IL-1 also enhanced the ovulatory effect of luteinizing hormone in the perfused rat ovary model. Taken together, the available evidence suggests a meaningful role for IL-1Aβ in the ovulatory cascade.