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This Article Full Text Full Text (PDF) All Versions of this Article: JOE-08-0250v1 199/2/191    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lee, Y. Articles by Lee, E. J. Search for Related Content PubMed PubMed Citation Articles by Lee, Y. Articles by Lee, E. J.

¹ Department of Internal Medicine² Graduate School³ Brain Korea 21 Project for Medical Science⁴ , Biochemistry and Molecular Biology⁵ Institute of Endocrine Research, Yonsei University College of Medicine, Seoul, South Korea⁶ Endocrinology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA

(Correspondence should be addressed to E J Lee at Endocrinology, Internal Medicine, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752, South Korea; Email: ejlee423{at}yuhs.ac)

^* Y Lee and J M Kim contributed equally to this work and should be considered co-first authors

The interaction of chemokine (C-X-C motif) ligand 12 (CXCL12) and its receptor CXCR4 may play an important role in the regulation of anterior pituitary function. In this study, we investigated the expression of CXCL12 and CXCR4 and their role in normal rat pituitary and GH-producing GH3 tumor cell line. RT-PCR analysis and immunohistochemistry revealed that CXCR4 was expressed in normal rat anterior pituitary and GH3 tumor cells. Double immunofluorescent staining showed the complete colocalization of CXCR4 with GH in rat pituitary, indicating that CXCR4 is specifically expressed in rat somatotrophs. Using rat primary pituitary cell cultures and GH releasing hormone receptor expressing stable GH3 cells (GH3-GHRHR), we evaluated the function of CXCL12 compared with GHRH. CXCL12 stimulated GH gene activation in both primary rat anterior pituitary cells and GH3-GHRHR cells. CXCL12 also stimulated GH secretion from primary rat pituitary cells in a dose-dependant manner. BrdU incorporation was increased in response to CXCL12 addition in GH3 cell culture, indicating CXCL12-induced cell proliferation. CXCL12-dependent phosphorylation of ERK1/2 was also confirmed by western blot analysis, supporting the evidence that MAPK is an intracellular mediator of CXCL12/CXCR4 interaction in GH3 cell proliferation. In conclusion, these results indicate that CXCL12/CXCR4 interaction plays an important role in GH production, secretion, and the proliferation of somatotrophs.