title: Effects of orchidectomy and testosterone replacement on mouse enkephalin-degrading aminopeptidase activity in the HPA axis.
abstract: Opiates are involved in the regulation of several functions in the hypothalamus-pituitary-adrenal (HPA) axis under physiological conditions. The aim of the present work is to study the influence of orchidectomy and testosterone (T) replacement on soluble (S) and membrane bound (MB) enkephalin-degrading aminopeptidase (EDA) activities in the HPA axis. Forty male mice (Balb/C) were distributed in five groups: sham-operated control (C), orchidectomized (OR-C), and orchidectomized treated with increasing doses of T (3, 6 or 12 mg/kg). In hypothalamus, orchidectomy did not modify either S or MB EDA, although T replacement increased S but not MB EDA. In pituitary, neither S nor MB EDA activities changed with orchidectomy, although both activities changed after T replacement. On the other hand, in adrenal glands, orchidectomy increased S and MB EDA activities, whereas T replacement returned both activities to control levels. These results suggest a direct effect of T in S and MB EDA activities and therefore, an influence on their endogenous substrates regulation.
authors.affiliation: Unit of Physiology, Department of Health Sciences, Faculty of Experimental and Health Sciences, University of Jaén, Campus de Las Lagunillas s/n, E-23071 Jaén, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: García-López
authors.forename: J M
authors.initials: JM
authors.lastname: Martínez-Martos
authors.forename: M D
authors.initials: MD
authors.lastname: Mayas
authors.forename: M P
authors.initials: MP
authors.lastname: Carrera
authors.forename: M J
authors.initials: MJ
authors.lastname: Ramírez-Expósito
mesh_terms: D000626:Aminopeptidases / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009919:Orchiectomy / Q000662:veterinary*; D010913:Pituitary-Adrenal System / Q000502:physiology*; D012995:Solubility; D013739:Testosterone / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D013739:Testosterone; D000626:Aminopeptidases; C025579:enkephalin degrading enzyme