Journal of Andrology Download to Citation Manager
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Published-Ahead-of-Print October 16, 2008
Journal of Andrology 2008, DOI:10.2164/jandrol.108.006155

This Article
Right arrow Author Manuscript (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Google Scholar
Right arrow Articles by Lysiak, J. J.
Right arrow Articles by Turner, T. T.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lysiak, J. J.
Right arrow Articles by Turner, T. T.

Hypoxia Inducible Factor-1alpha Is Constitutively Expressed in Murine Leydig Cells and Regulates 3beta-Hydroxysteroid Dehydrogenase Type I Promoter Activity

Jeffrey J. Lysiak *, Jennifer L. Kirby , Jacques J. Tremblay , Robin I. Woodson , Michael A. Reardon , Lisa A. Palmer , and Terry T. Turner

* To whom correspondence should be addressed. E-mail: jl6n{at}virginia.edu.

Hypoxia inducible factor (HIF)-1alpha is a transcription factor that plays an essential role in oxygen homeostasis. HIF-1alpha is constitutively made in cells; however, it is ubiquitinated and degraded under normoxic conditions. Hypoxia prevents the ubiquitination of HIF-1alpha resulting in stabilization of the protein and activation of target genes. Because of its vascular arrangement and the high metabolic demand of spermatogenesis the testis has previously been described as functioning on the brink of hypoxia; thus, we have hypothesized that HIF-1alpha is constitutively expressed and stabilized in the testis where it could play a role in testicular homeostasis. Western blot analysis using nuclear proteins from liver, kidney, and testis revealed the presence of HIF-1alpha only in the testis. Immunohistochemistry confirmed this result and revealed that HIF-1alpha was specifically located in interstitial Leydig cells. Electromobility shift assays (EMSAs) employing nuclear extracts from the TM3 Leydig cell line revealed that these cells express functionally active HIF-1alpha under normoxic conditions. Furthermore, we found that protein levels can be further increased when the TM3 cells are cultured under hypoxic conditions. Finally, transient transfections of TM3 Leydig cells revealed that the promoter of the mouse 3beta hydroxysteroid dehydrogenase type I (Hsd3b1) gene, which encodes a key enzyme in testosterone production, is a potential target of HIF-1alpha. In conclusion, HIF-1alpha is constitutively present in Leydig cells of the murine testis where it potentially regulates Hsd3b1 transcription and thus male reproductive function.


Key words: Reproductive Tract • Steroidogenesis • Testis






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Copyright © 2008 by The American Society of Andrology.