title: Evidence for active transport of 3H-androgens across the epididymal epithelium in the rat.
abstract: The effect of metabolic inhibitors on transepithelial movement of 3H-androgens was investigated by in vivo perifusion and subsequent micropuncture of caput and cauda epididymal tubules. Epididymal tissue (adenosine triphosphate (ATP) concentrations were determined at 1 h after exposure of perifusion fluid with metabolic inhibitor. To determine whether or not metabolic inhibitor alters intraluminal androgen-binding protein concentration or androgen binding to interstitial proteins in the caput epididymis, 3H-dihydrotestosterone (DHT) binding to interaluminal androgen-binding protein and bound vs free androgen ratio in the interstitial fluid after 1 h perifusion with fluid containing metabolic inhibitor around caput epididymal tubules were examined. Proluminal movement of 3H-androgens and tissue ATP concentrations in the caput and cauda epididymis were significantly decreased by addition of dinitrophenol (DNP) or potassium cyanide to the perifusion fluid. Relative intraluminal androgen-binding protein protein concentration and bound vs free 3H-androgen ratio in the interstitial fluid were not altered when DNP or potassium cyanide was added to the perifusion fluid. These results demonstrate for the first time that an energy-dependent mechanism may be involved in the epididymal androgen uptake.
authors.affiliation: Department of Urology, Nagoya University School of Medicine, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Tsuji
authors.forename: K
authors.initials: K
authors.lastname: Miyake
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D013196:Dihydrotestosterone / Q000493:pharmacokinetics*; D004822:Epididymis / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D008297:Male; D051381:Rats; D014316:Tritium
chemical_list: D013196:Dihydrotestosterone; D014316:Tritium