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This Article Full Text Full Text (PDF) All Versions of this Article: JME-08-0066v1 42/2/171    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 HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Ellestad, L. E Articles by Porter, T. E Search for Related Content PubMed PubMed Citation Articles by Ellestad, L. E Articles by Porter, T. E

¹ Molecular and Cell Biology Program, University of Maryland, College Park, Maryland 20742, USA² Department of Animal and Avian Sciences, University of Maryland, Building 142, Room 1403, College Park, Maryland 20742, USA³ Animal Biosciences and Biotechnology Laboratory, Agricultural Research Service, US Department of Agriculture, Beltsville, Maryland 20705, USA

(Correspondence should be addressed to T E Porter; Email: teporter{at}umd.edu)

The expression profile of glucocorticoid-induced leucine zipper (GILZ) in the anterior pituitary during the second half of embryonic development in the chick is consistent with in vivo regulation by circulating corticosteroids. However, nothing else has been reported about the presence of GILZ in the neuroendocrine system. We sought to characterize expression and regulation of GILZ in the chicken embryonic pituitary gland and determine the effect of GILZ overexpression on anterior pituitary hormone levels. Pituitary GILZ mRNA levels increased during embryogenesis to a maximum on the day of hatch, and decreased through the first week after hatch. GILZ expression was rapidly upregulated by corticosterone in embryonic pituitary cells. To determine whether GILZ regulates hormone gene expression in the developing anterior pituitary, we overexpressed GILZ in embryonic pituitary cells and measured mRNA for the major pituitary hormones. Exogenous GILZ increased prolactin mRNA above basal levels, but not as high as that in corticosterone-treated cells, indicating that GILZ may play a small role in lactotroph differentiation. The largest effect we observed was a twofold increase in FSH β subunit in cells transfected with GILZ but not treated with corticosterone, suggesting that GILZ may positively regulate gonadotroph development in a manner not involving glucocorticoids. In conclusion, this is the first report to characterize avian GILZ and examine its regulation in the developing neuroendocrine system. We have shown that GILZ is upregulated by glucocorticoids in the embryonic pituitary gland and may regulate expression of several pituitary hormones.

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				E. Ayroldi and C. Riccardi Glucocorticoid-induced leucine zipper (GILZ): a new important mediator of glucocorticoid action FASEB J, November 1, 2009; 23(11): 3649 - 3658. [Abstract] [Full Text] [PDF]