In vivo activation of the interleukin-6 receptor/gp130 signaling pathway in pituitary corticotropes of lipopolysaccharide-treated rats

Laurent Gautron, Pierrette Lafon, Gérard Tramu, Sophie Layé

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Adrenocorticotropic hormone (ACTH) release from anterior pituitary corticotropes is greatly increased during peripheral inflammation induced by lipopolysaccharide (LPS) administration. Interleukin-6 (IL-6) is thought to participate in LPS-induced ACTH release, but whether or not corticotropes are directly targeted by this cytokine is unclear. Therefore, we investigated the expression and activation of IL-6 signaling components in the pituitary of rats 2 and 4 h after administration of LPS (250 μg/kg). Intraperitoneal LPS treatment provoked the nuclear translocation of signal transducer and activator of transcription 3 (STAT-3) and Fos expression in the anterior pituitary lobe, as demonstrated by immunohistochemistry. By using in situ hybridization, we demonstrated that suppressor of cytokine signaling 3 (SOCS-3) and c-fos mRNAs were significantly induced by the LPS treatment in the anterior lobe of the pituitary. Dual in situ hybridization revealed that most corticotropes expressed IL-6 receptor and gp130 mRNAs, and that 2 h after LPS treatment, SOCS-3 and c-fos mRNAs were induced in corticotropes. Our results suggest that LPS-induced IL-6 could regulate the hypothalamo-pituitary-adrenal axis by directly targeting corticotropes during peripheral inflammation.

Original languageEnglish (US)
Pages (from-to)32-43
Number of pages12
JournalNeuroendocrinology
Volume77
Issue number1
DOIs
StatePublished - Mar 20 2003

Keywords

  • Corticotropes
  • Fos
  • Immunocytochemistry
  • In situ hybridization
  • Inflammation
  • Interleukins
  • Lipopolysaccharide
  • Neuroimmune interactions
  • Proopiomelanocortin
  • STAT-3

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Endocrine and Autonomic Systems
  • Cellular and Molecular Neuroscience

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