LPS-Induced Inflammation Potentiates the IL-1-Mediated Reduction of LH Secretion from the Anterior Pituitary Explants

Abstract

Acting at the level of the brain, interleukin- (IL-)1β is considered to be one of the most potent downregulators of reproduction processes during immune/inflammatory challenge. IL-1β suppresses gonadotropin-releasing hormone (GnRH) secretion from the hypothalamus resulting in the inhibition of the luteinizing hormone (LH) release from the anterior pituitary (AP). However, the presence of IL-1β receptors in the AP suggests the possible direct action of this cytokine on LH secretion. The study was designed to determine the effect of IL-1β on the LH secretion from the AP explants collected from saline and LPS-treated ewes in the follicular phase. It was found that IL-1β suppressed (P ≤ 0.01) GnRH-stimulated LH release and LHβ gene expression in AP explants in both groups. However, IL-1β action was more potent in the explants collected from LPS-treated animals. Pituitaries from LPS-treated animals were characterized by increased (P ≤ 0.01) IL-1 type I receptor and decreased (P ≤ 0.01) GnRH receptor gene expression level compared to the saline-treated group. IL-1β also affected the GnRH-R gene expression in explants collected from LPS-treated animals. Our results show that direct action of IL-1β on the pituitary gonadotropes could be one of the reasons of the reproductive processes disorders accompanying an inflammatory state.

Photoperiod-dependent effect of inflammation on nocturnal gene expression of proinflammatory cytokines and their receptors in <i>pars tuberalis</i> of ewe

“…It was also found that IL-1β increased the adrenocorticotropic hormone, LH, GH and TSH secretion in primary cultures of rat pituitary cells, while IL-6 stimulated prolactin, GH, FSH and LH release from rat pituicytes culture (Tsagarakis et al, 1998). On the other hand, the study performed on the sheep pituitary explants showed that IL-1β suppressed LH secretion (Herman et al, 2013).…”

How does bacterial endotoxin influence gonadoliberin/gonadotropins secretion and action?

“…In in vitro study on the cells from ovine pituitary gland, Braden et al (1998) showed that IL-1β and IL-1α stimulated the release of LH. However, the results of our ex vivo study on the ovine pituitary explants showed that IL-1β rather down-regulated LH secretion from the pituitary gland (Herman et al, 2013b). This suggests that circulating proinflammatory cytokines, particularly IL-1β released during an inflammatory condition, may directly affect LH secretion from the anterior pituitary cells and this direct mechanism may accompany the processes occurring at the level of hypothalamus.…”

Total Testosterone and Sex Hormone-Binding Globulin as Predictor Markers of Metabolic Syndrome among Obese People from Basrah

“…14 Previous studies found that inflammatory cytokines may have a direct effect on the pituitary gland to decrease LH secretion, and a direct effect on secretion of testosterone from the Leydig cell (these two factors will reduce TT). 15,16 There is dysregulation hypothalamic pituitary adrenal axis due to increased glucocorticoid production among obese patients and subsequent hypoandrogenism in men. 17 Additional evidence that low TT which caused by androgen deprivation treatment in patients with prostate cancer may lead to increases the risk of MetS as seen in Basaria et al, study.…”