title: Expression of human GLUD1 and GLUD2 glutamate dehydrogenases in steroid producing tissues.
abstract: Besides the housekeeping glutamate dehydrogenase1 (hGDH1), humans have acquired, via a recent duplication event, a hGDH2 isoenzyme with distinct functional properties and tissue expression profile. GDH catalyzes the reversible deamination of glutamate to α-ketoglutarate while reducing NAD(P) to NAD(P)H. As the generated NADPH can be used in bio-synthetic pathways, we studied here the expression of hGDH1 and hGDH2 in human steroidogenic tissues using specific antibodies. Results revealed high levels of hGDH1 and hGDH2 expression in steroid-producing cells in all tissues studied. While the cellular expression pattern of the two proteins was similar for the adrenal cortex, it was distinct for testis, ovaries and placenta. Functional analyses revealed that steroid hormones interacted differentially with the two isoenzymes. As synthesis of steroid hormones requires NADPH, expression of hGDH1 and hGDH2 in steroidogenic cells may serve their particular metabolic needs.
authors.affiliation: Department of Neurology, Faculty of Medicine, School of Health Sciences, University of Crete, Heraklion, Greece. Electronic address: kliospanaki@gmail.com.
authors.forename: Cleanthe
authors.initials: C
authors.lastname: Spanaki
authors.affiliation: Department of Neurology, Faculty of Medicine, School of Health Sciences, University of Crete, Heraklion, Greece.
authors.forename: Dimitra
authors.initials: D
authors.lastname: Kotzamani
authors.affiliation: Department of Neurology, Faculty of Medicine, School of Health Sciences, University of Crete, Heraklion, Greece.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Petraki
authors.affiliation: Department of Pathology, Faculty of Medicine, School of Health Sciences, University of Crete, Heraklion, Greece.
authors.forename: Elias
authors.initials: E
authors.lastname: Drakos
authors.affiliation: Department of Neurology, Faculty of Medicine, School of Health Sciences, University of Crete, Heraklion, Greece.
authors.forename: Andreas
authors.initials: A
authors.lastname: Plaitakis
mesh_terms: D000302:Adrenal Cortex / Q000378:metabolism*; D000818:Animals; D005260:Female; D005969:Glutamate Dehydrogenase / Q000378:metabolism*; D006801:Humans; D008297:Male; D009249:NADP / Q000378:metabolism; D009928:Organ Specificity; D010053:Ovary / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D061987:Sf9 Cells; D013256:Steroids / Q000378:metabolism; D013737:Testis / Q000378:metabolism*
chemical_list: D013256:Steroids; D009249:NADP; D005969:Glutamate Dehydrogenase; C561840:GLUD1 protein, human; C521120:GLUD2 protein, human
keywords: Enzyme kinetics; Glutamate dehydrogenase; Immunohistochemistry; Steroid hormone; Steroidogenesis