title: Different mechanisms are responsible for 3H-androgen movement across the rat seminiferous and epididymal epithelia in vivo.
abstract: Mechanisms involved in the maintenance of the microenvironment of the seminiferous and epididymal tubules were examined in a series of experiments utilizing in vivo microperifusion, microperfusion, and micropuncture. Intraluminal 3H-androgen concentrations in seminiferous tubules increased linearly as interstitial 3H-androgen concentrations increased from 10 nM to 2,000 nM, but in caput epididymidal tubules, intraluminal 3H-androgen concentrations increased hyperbolically across the same range of peritubular 3H-androgen concentrations. Intraluminal 3H-androgen concentrations in the caput epididymidis did not rise above approximately 340 nM even if peritibular 3H-androgen concentrations exceeded 2,000 nM. Perifusion of caput tubules with 0.1 mM dinitrophenol or potassium cyanide or 100 micrograms/ml cyclohexamide significantly reduced proluminal 3H-androgen movement, but tubules perifused with control medium would not support antigrade 3H-androgen movement in the absence of native lumen fluids which contain androgen-binding protein. Antigrade proluminal 3H-androgen movement was not inhibited by competition with estradiol at ten-times 3H-androgen concentrations. Thus, energy-requiring protein synthesis is necessary for antigrade 3H-androgen movement in the caput epididymidis, but the mechanism for the interaction of intracellular protein(s) and 3H-androgen movement remains undetermined.
authors.affiliation: Department of Urology, University of Virginia Health Sciences Center, Charlottesville 22908.
authors.forename: T T
authors.initials: TT
authors.lastname: Turner
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
mesh_terms: D019297:2,4-Dinitrophenol; D000255:Adenosine Triphosphate / Q000378:metabolism; D000727:Androgen-Binding Protein / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D003513:Cycloheximide / Q000494:pharmacology; D004140:Dinitrophenols / Q000494:pharmacology; D004822:Epididymis / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism; D008297:Male; D011190:Potassium Cyanide / Q000494:pharmacology; D014176:Protein Biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D012671:Seminiferous Tubules / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism*
chemical_list: D000727:Androgen-Binding Protein; D004140:Dinitrophenols; D013739:Testosterone; D004958:Estradiol; D000255:Adenosine Triphosphate; D003513:Cycloheximide; D011190:Potassium Cyanide; D019297:2,4-Dinitrophenol