title: Expression of aquaporin 9 in the adult rat epididymal epithelium is modulated by androgens.
abstract: Reabsorption of fluid and solutes across the epithelium lining the male excurrent duct is important for adequate sperm maturation, concentration, and storage. Water channels contribute to water movement across epithelia in many tissues. Aquaporin 9 (AQP9) is abundantly expressed in the apical membrane of principal cells that line the epididymis, and in reabsorptive and secretory epithelial cells of the male reproductive tract. In this study we show that the nonsteroidal antiandrogen flutamide, given to adult rats at a dose of 50 mg x kg(-1) x day(-1) for 2 wk via osmotic minipumps significantly decreased the amount of AQP9 in the epididymis. This down-regulation was observed by immunofluorescence of cryostat tissue sections and by Western blotting of epididymal brush border membrane preparations. In addition, castrated adult rats showed lower levels of epididymal AQP9 compared with adult controls, whereas systemic testosterone treatment of castrated adult rats induced a recovery of the expression of AQP9 to control levels. These data indicate that the expression of AQP9, a likely candidate for apical transepithelial fluid and solute transport in several regions of the male reproductive tract, is modulated by androgens in the adult rat epididymis.
authors.affiliation: Renal Unit and Program in Membrane Biology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: Nuria
authors.initials: N
authors.lastname: Pastor-Soler
authors.forename: Corinne
authors.initials: C
authors.lastname: Isnard-Bagnis
authors.forename: Carol
authors.initials: C
authors.lastname: Herak-Kramberger
authors.forename: Ivan
authors.initials: I
authors.lastname: Sabolic
authors.forename: Alfred
authors.initials: A
authors.lastname: Van Hoek
authors.forename: Dennis
authors.initials: D
authors.lastname: Brown
authors.forename: Sylvie
authors.initials: S
authors.lastname: Breton
mesh_terms: D000726:Androgen Antagonists / Q000494:pharmacology; D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D020346:Aquaporins / Q000032:analysis / Q000235:genetics*; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D004822:Epididymis / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005485:Flutamide / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D008297:Male; D008871:Microvilli / Q000737:chemistry; D009919:Orchiectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013739:Testosterone / Q000494:pharmacology
chemical_list: D000726:Androgen Antagonists; D000728:Androgens; C491637:Aqp9 protein, rat; D020346:Aquaporins; D013739:Testosterone; D005485:Flutamide