title: Gene expression is differentially regulated in the epididymis after orchidectomy.
abstract: The epididymis is the site for the transport, maturation, and storage of spermatozoa. Regulation of epididymal structure and function is highly dependent on the ipsilateral testis. At the molecular level, however, few studies have been undertaken to determine which genes are expressed in the epididymis under testicular regulation. The goal of this study was to identify genes for which expression is regulated after orchidectomy, both throughout the epididymis and in a segment-specific manner. Microarrays spotted with 474 rat cDNAs were used to examine gene expression changes over the first 7 d post orchidectomy in the initial segment, caput, corpus, and cauda epididymidis of the adult Brown Norway rat. Using k-means cluster analysis, we show that four patterns of gene expression are activated in each epididymal segment over the first week following orchidectomy. Transient up-regulation of gene expression in the epididymis after orchidectomy is described for the first time. Potential androgen-repressed genes, including Gpx-1, show increased expression in the epididymis after orchidectomy. Several glutathione-S-transferases and calcium-binding proteins decline throughout the epididymis after orchidectomy, indicating that these may be novel androgen-regulated epididymal genes. Other genes coding for metabolism-associated proteins, transporters, and alpha-1 acid glycoprotein show segment-specific regulation in the epididymis after orchidectomy. Finally, we describe the expression of the previously uncharacterized heat shock proteins, and apoptosis-associated genes in the epididymis after orchidectomy. Thus, gene expression in the epididymis is differentially affected over time after orchidectomy. These results provide novel insight into androgen-dependent and segment-specific epididymal function.
authors.affiliation: Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada.
authors.forename: Nadine
authors.initials: N
authors.lastname: Ezer
authors.forename: Bernard
authors.initials: B
authors.lastname: Robaire
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D001219:Aspartate Aminotransferases / Q000235:genetics; D002135:Calcium-Binding Proteins / Q000235:genetics; D004822:Epididymis / Q000378:metabolism*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005982:Glutathione Transferase / Q000235:genetics; D006360:Heat-Shock Proteins / Q000235:genetics; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D009919:Orchiectomy; D009955:Ornithine Decarboxylase / Q000235:genetics; D009961:Orosomucoid / Q000235:genetics; D051381:Rats; D011914:Rats, Inbred BN; D013739:Testosterone / Q000235:genetics; D013997:Time Factors
chemical_list: D002135:Calcium-Binding Proteins; D006360:Heat-Shock Proteins; D009961:Orosomucoid; D013739:Testosterone; D005982:Glutathione Transferase; D001219:Aspartate Aminotransferases; D009955:Ornithine Decarboxylase