title: Identification of early response genes and pathway activated by androgens in the initial segment and caput regions of the regressed rat epididymis.
abstract: To identify the initial response to androgens and estrogens in the orchidectomized, regressed epididymis, we determined the gene expression changes triggered by the administration of either of two metabolites of testosterone, 5alpha-dihydrotestosterone (DHT) or 17beta-estradiol (E2), in the regressed rat epididymis. Adult rats were orchidectomized and 8 d later implanted with either empty implants (control), DHT-filled-, or E2-filled-polydioxanone implants. Rats were euthanized 12 h, 1 d, and 7 d later, and RNA was extracted and probed on Rat230-2.0 Affymetrix arrays. Probe sets that respond to DHT or E2 were identified at early time points; although the expression of some was repressed, the expression of many others was either transiently or chronically elevated. Nerve growth factor receptor (Ngfr) and S100 calcium binding protein G (S100g) were two E2 up-regulated genes detected at 12 h. Among the genes that showed a dramatic early response to DHT were endothelin 1 (Edn1), bone morphogenetic protein 4 (Bmp4), and IGF binding protein 3 (Igfbp3), which were suppressed, and IGF-I (Igf1), which was induced. Genes that were up- or down-regulated by DHT were classified based on biological function. Using PathwayStudio 4.0, we identified genes that were linked and directly influenced either the expression or regulation of one another. Epidermal growth factor and IGF-I play an important role in the pathway due to their function in regulation and expression of many other genes. These results provide novel insights into the impact of androgen action on the expression of genes that are important for epididymal function.
authors.affiliation: Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G1Y6.
authors.forename: Mahsa
authors.initials: M
authors.lastname: Hamzeh
authors.forename: Bernard
authors.initials: B
authors.lastname: Robaire
mesh_terms: D015068:17-Ketosteroids / Q000494:pharmacology*; D000732:Androstanols / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D016000:Cluster Analysis; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism; D004822:Epididymis / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D004958:Estradiol / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects*; D020869:Gene Expression Profiling; D053263:Gene Regulatory Networks; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D009919:Orchiectomy; D051381:Rats; D011914:Rats, Inbred BN; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics; D013997:Time Factors
chemical_list: D015068:17-Ketosteroids; C418023:5-dihydrorubrosterone; D000732:Androstanols; D019332:Endothelin-1; D004958:Estradiol; D007334:Insulin-Like Growth Factor I