Expression and Localization of Hypoxia-Inducible Factor-1 Subunits in the Adult Rat Epididymis

Abstract The epididymal epithelium contributes to formation of a luminal fluid that is essential for the protection of spermatozoa from a variety of insults including changes in oxygen tension. A key regulator of the response to oxygen debt in many cells is hypoxia-inducible factor-1 (HIF-1). A transcription factor composed of α and β subunits, HIF-1 activates genes that mediate oxygen homeostasis and cell survival pathways or trigger cell death responses. Previously we have shown that HIF-1α mRNA is expressed in the adult rat epididymis. Goals of this study were to determine whether HIF-1α protein is activated by ischemia in the rat epididymis, to determine whether epididymal HIF-1α mRNA expression is androgen dependent, and to identify epididymal cell types expressing HIF-1α and β. Immunoblot analysis revealed that HIF-1α protein is primarily present in corpus and cauda of the normoxic epididymis and unaffected by ischemia, whereas HIF-1β was detected equally in all regions and also unaffected by ischem...