Transcriptional and Posttranscriptional Regulation of Intraovarian Insulin-Like Growth Factor-Binding Proteins by Interleukin-1β (IL-1β): Evidence for IL-1β as an Antiatretic Principal

Intraovarian interleukin-1 (IL-1), a putative intermediary in the ovulatory cascade, has recently been implicated as an antiatretic agent. Given the reported antigonadotropic and thus atretogenic potential of granulosa cell-derived insulin-like growth factor-binding proteins (IGFBPs), we evaluated the ability of IL-1β to regulate ovarian IGFBP-4 and -5, the IGFBP species elaborated by the rat granulosa cell. Treatment of whole ovarian dispersates of immature rat origin with increasing concentrations of IL-1β for 96 h resulted in substantial and significant time-dependent inhibition of IGFBP-4 and IGFBP-5 transcripts compared with that in untreated controls. The IL-1 effect proved relatively specific in that no significant alterations in IGFBP transcripts were observed in the presence of select ovarian agonists, including transforming growth factor-α, tumor necrosis factor-α, endothelin-1, hepatocyte growth factor, keratinocyte growth factor, or basic fibroblast growth factor. The inhibitory effect of IL-1...