title: Dehydroepiandrosterone (DHEA) metabolism in the brain: identification by liquid chromatography/mass spectrometry of the delta-4-isomer of DHEA and related steroids formed from androstenedione by mouse BV2 microglia.
abstract: Studies to elucidate the role of dehydroepiandrosterone (DHEA) metabolism in neuroprotection have compared its relative 7-hydroxylation against estrogen formation by way of 4-androstenedione (AD) in various rodent brain cell lines. In all cases, the 7alpha- and 7beta-hydroxy epimers of DHEA were found to be the dominant products with one notable exception. BV2 mouse microglia were virtually unable to hydroxylate DHEA at C-7 and converted AD to a major unknown metabolite not observed with mouse BHc hippocampal cells. In this paper, we describe the identification of this compound based on its physical properties and analysis by TLC and HPLC. Its identity as 3beta-hydroxy-4-androstene-17-one, the Delta(4)-isomer of DHEA, was confirmed by mass spectrometry (LC/MS), as well as by reverse isotope dilution analysis involving co-crystallization with the synthetic steroid. Possible mechanisms for the formation of this isomer of DHEA by BV2 microglia are proposed, together with that of other C-19 steroids detected which include testosterone (T), 5alpha-dihydrotestosterone and 5alpha-androstanedione.
authors.affiliation: Department of Biochemistry, Queen's University, Kingston, Ont., Canada K7l 3N6.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Jellinck
authors.forename: Martin
authors.initials: M
authors.lastname: Kaufmann
authors.forename: Andres
authors.initials: A
authors.lastname: Gottfried-Blackmore
authors.forename: Gist
authors.initials: G
authors.lastname: Croft
authors.forename: Valarie
authors.initials: V
authors.lastname: Byford
authors.forename: Bruce S
authors.initials: BS
authors.lastname: McEwen
authors.forename: Glenville
authors.initials: G
authors.lastname: Jones
authors.forename: Karen
authors.initials: K
authors.lastname: Bulloch
mesh_terms: D000276:Adjuvants, Immunologic / Q000378:metabolism; D000735:Androstenedione / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002853:Chromatography, Liquid; D003687:Dehydroepiandrosterone / Q000031:analogs & derivatives / Q000378:metabolism*; D013058:Mass Spectrometry; D051379:Mice; D017628:Microglia / Q000378:metabolism*; D013256:Steroids
chemical_list: D000276:Adjuvants, Immunologic; D013256:Steroids; D000735:Androstenedione; D003687:Dehydroepiandrosterone