title: Characterization of 11beta-hydroxysteroid dehydrogenase activity in testicular tissue of control and GnRH-immunized boars as a possible regulator of spermatogenesis.
abstract: Glucocorticoids are involved in the regulation of spermatogenesis in the boar testis by initiating apoptosis in early stages of germ cell development. Because cortisol activity is modulated by the 11beta-hydroxysteroid dehydrogenase system (11beta-HSD), the present study determined both 11beta-activating (reductive) and inactivating (oxidative) enzyme activities in testicular tissue preparations of control boars (n = 5), GnRH-immunized boars (n = 5), and immunized, estradiol-infused boars (n = 6) by radioenzyme assay based on the conversion of tritiated cortisol to cortisone in the presence of NAD+ (inactivation) or tritiated cortisone to cortisol in the presence of NADPH (activation). The presence of both isoforms, 11beta-HSD 1 and 11beta-HSD 2, was confirmed by RTPCR in testicular tissue of control boars. Additionally, cortisol, testosterone, estradiol, and LH were determined in blood plasma sampled twice before killing. Immunization led to a drop of LH from 4.3 +/- 0.3 pmol/L to 1.0 +/- 0.3 pmol/L (testosterone: 11.63 +/- 0.83 nmol/L vs. 0.28 +/- 0.07 nmol/L; 17beta-estradiol: 512.61 +/- 47.60 pmol/L vs. 77.05 +/- 14.00 pmol/L). Low 11beta-HSD reductive activity was found in boars (1 pmol steroid x min (-1) x mg (-1)). It decreased to trace amounts in immunized boars (0.07 pmol steroid x min (-1) x mg (-1)). Oxidative activity was found in boars with 10.19 +/- 2.28 pmol steroid x min (-1) x mg (-1) protein. Immunization led to a sharp decrease (0.08 +/- 0.03 pmol x min (-1) x mg (-1)). Infusion of 17beta-estradiol significantly elevated peripheral estradiol concentrations to 752.07 +/- 24.19 pmol/L which still is a physiological concentration in this species. The infusion led to a minimal reductive activity (0.04 pmol steroid x min (-1) x mg (-1)), but led to a 6-fold rise of the 11beta-HSD oxidative activity to 0.47 +/- 0.14 pmol x min (-1) x mg (-1) compared to immunized boars. It is concluded that the 11beta-HSD system is involved in the regulation of cortisol activity in the testis and thus in the regulation of spermatogenesis.
authors.affiliation: Universität Hohenheim, Institut für Tierhaltung und Tierzüchtung, Fachgebiet Tierhaltung und Leistungsphysiologie (470 A), Stuttgart, Germany. thsekret@uni-hohenheim.de
authors.forename: R
authors.initials: R
authors.lastname: Claus
authors.forename: A
authors.initials: A
authors.lastname: Wagner
authors.forename: T
authors.initials: T
authors.lastname: Lambert
mesh_terms: D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1 / Q000235:genetics / Q000378:metabolism; D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2 / Q000235:genetics / Q000378:metabolism; D042842:11-beta-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000818:Animals; D003348:Cortisone / Q000378:metabolism; D004958:Estradiol / Q000008:administration & dosage; D007987:Gonadotropin-Releasing Hormone / Q000276:immunology* / Q000502:physiology*; D006706:Homeostasis; D006854:Hydrocortisone / Q000097:blood / Q000378:metabolism; D007114:Immunization; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D009243:NAD / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013091:Spermatogenesis / Q000502:physiology*; D013552:Swine / Q000502:physiology*; D013737:Testis / Q000201:enzymology*
chemical_list: D009243:NAD; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D007986:Luteinizing Hormone; D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1; D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2; D042842:11-beta-Hydroxysteroid Dehydrogenases; D003348:Cortisone; D006854:Hydrocortisone