Interleukin-1β Stimulates Nitrite Production in the Rat Ovary: Evidence for Heterologous Cell-Cell Interaction and for Insulin-Mediated Regulation of the Inducible Isoform of Nitric Oxide Synthase1

Abstract

Recent studies suggest that endogenously generated nitric oxide (NO) may mediate the effects of cytokines in a variety of tissues. In an effort to determine whether NO generation mediates any of the intraovarian actions of interleukin-1 beta (IL-1 beta), we have looked for and characterized the accumulation of nitrite by IL-1 beta-treated, cultured whole ovarian dispersates. Application of IL-1 beta significantly enhanced basal nitrite release in a dose-, cell density- and time-dependent manner, the latter characterized by a lag time of about 20 h, suggestive of induction of NO synthase (NOS). Cellular NOS activity was also elevated by IL-1 beta. Sustained nitrite accumulation required continuous application of IL-1 beta. The maximally stimulating dose of IL-1 beta (50 ng/ml) produced a 10-fold increase in nitrite accumulation by 96 h of culture, an effect reduced 23% when cells were cultured in substrate (i.e., arginine)-free media. IL-1 beta-stimulated nitrite accumulation was reduced to control levels by the simultaneous application of an IL-1 beta receptor antagonist, thereby suggesting a specific receptor-mediated effect. Both the control and IL-1 beta-stimulated levels of nitrite accumulation were attenuated in a dose-dependent manner by inhibitors that favor the inducible form of NOS. In contrast, selective inhibitors of the constitutive form of NOS were significantly less potent. No inhibition was noted after application of an inactive stereoisomeric analogue. IL-1 beta-induced nitrite accumulation was shown to require cell-cell interaction between granulosa and theca-interstitial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Interactions between interleukin-1 beta, nitric oxide and prostaglandin E2 in the rat ovary: effects on steroidogenesis

“…The finding that IL-1 b did not increase nitrite production in GL cells agrees with the observations of Ben-Shlomo et al (14) who showed that the cytokine only induced significant nitrite accumulation in cultures of ovarian cells and in granulosa cells cultured with thecal cells. GL cells or thecal cells cultured on their own did not produce significant concentrations of nitrites in the presence of IL-1 b , suggesting that some cell-cell interaction is required for the induction of inducible NO synthase (iNOS).…”

“…1). Based on our previous experiments (7) and other reports (8,14) 20 ng/ml IL-1 b is considered to be a maximal dose of this cytokine and thus used throughout the experiments.…”

Changes in Nitric Oxide Synthase Activity in the Ovary of Gonadotropin Treated Rats. The Role of Nitric Oxide during Ovulation.

“…There are reports suggesting iNOS involvement in the ovulatory process [7,8]. Current reports indicate that IL-1, which plays an important role in ovarian function [22,28,29], utilizes NO to influence the ovarian cells [30][31][32]. The IL-1fi mRNA expression in the ovary shows a narrow peak at 6 h after hCG injection [33].…”

Modulatory Action of Nitric Oxide on the Expression of Transcription Factor Genes, c-fos and c-jun, in Developing Porcine Granulosa Cells In Vitro.

“…46: [167][168][169][170][171][172][173][174][175] 2000) The expression of mRNAs and proteins for eNOS and iNOS in the rat ovary has been shown during follicular development, ovulation and pseudopregnancy [8,9]. In rat and human ovarian cells, NO has been shown to be involved in folliculogenesis, ovulation and steroidogenesis [10][11][12][13][14][15]. In our previous study using rat granulosa cells [16], NO was proposed as functioning as a modulator in cell differentiation, because removal of NO during cell differentiation suppressed itric oxide (NO) is a short-lived messenger molecule that mediates a variety of cellular functions.…”