Localization of interleukin-18 and its receptor in somatotrophs of the bovine anterior pituitary gland

Yasuhiro Nagai, Tomonori Nochi, Kouichi Watanabe, Keisuke Watanabe, Hisashi Aso, Haruki Kitazawa, Masatoshi Matsuzaki, Shyuichi Ohwada, Takahiro Yamaguchi

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

A pro-inflammatory cytokine, interleukin 18 (IL-18), induces intracellular expression of IL-1 and the release of IL-6. IL-1 and IL-6 has been detected in anterior pituitary cells, suggesting that IL-18 is produced in anterior pituitary cells and may serve to aid immuno-endocrine regulation. In the present study, we addressed this hypothesis by investigating the intracellular localization of IL-18 and its receptor in bovine anterior pituitary gland. IL-18 mRNA and its protein were detected in the anterior pituitary gland by RT-PCR and Western blotting. In situ hybridization showed that IL-18 mRNA was expressed in the anterior pituitary cells. Immunohistochemistry of IL-18 and specific hormones revealed the presence of IL-18 in somatotrophs. Furthermore, the expression of GH mRNA in IL-18 immunoreactive cells was confirmed by immuno-laser microdissection. These results first demonstrated that somatotrophs produced IL-18. Subsequently, the distribution of the IL-18 receptor alpha (IL-18Rα) was investigated in order to understand IL-18 signaling among the anterior pituitary cells. Bovine IL-18Rα cDNA was partially sequenced and detected in the anterior pituitary gland by RT-PCR. Immunohistochemistry of IL-18Rα, IL-18 and GH showed that IL-18Rα was co-localized in IL-18 immunoreactive cells or somatotrophs. These data suggest that IL-18 acts on somatotrophs as an immuno-endocrine mediator through the autocrine pathway.

Original languageEnglish
Pages (from-to)455-462
Number of pages8
JournalCell and Tissue Research
Volume322
Issue number3
DOIs
Publication statusPublished - 2005 Dec

Keywords

  • Anterior pituitary gland
  • Bovine
  • Immuno-endocrine signaling
  • Interleukin-18
  • Interleukin-18R
  • Somatotroph

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology
  • Cell Biology

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