Chapter 15 - Potential Role of Cytokines in Ovarian Physiology: The Case for Interleukin-1

Abstract

This chapter discusses in detail the various roles that interleukin-1 (IL-1) plays in folliculogenesis, ovulation, and regulation of corpus luteum function. Cytokines are important intra-ovarian regulators in the mammalian ovary. The emerging concept is that the cytokines are instrumental in the regulation of folliculogenesis, ovulation, and corpus luteum function. The cytokines in the ovary are secreted both from immune cells that have been recruited from the blood circulation to the extravascular space in the ovarian stroma and the theca layer of the follicle, and also from the somatic cells of the ovary, including the granulosa and theca cells. A number of cytokines, such as interferon γ, granulocyte-macrophage colony–stimulating factor, interleukin-6, and tumor necrosis factor-α, have been linked to some of these cyclic ovarian events. However, interleukin-1 (IL-1) stands out as a cytokine, which has major effects on functional and structural alterations within the ovary at all stages of the ovarian cycle. The polypeptide cytokine IL-1 is the term for two polypeptides, interleukin-1 α (IL-1 α) and interleukin-1β (IL-1 β). They are initially synthesized as 31 kD precursors (pro-IL-1), which are further cleaved to generate mature IL-1.