title: Rapid estrogen regulation of DHEA metabolism in the male and female songbird brain.
abstract: In the songbird brain, dehydroepiandrosterone (DHEA) is metabolized to the active and aromatizable androgen androstenedione (AE) by 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4 isomerase (3beta-HSD). Thus, brain 3beta-HSD plays a key role in regulating the steroidal milieu of the nervous system. Previous studies have shown that stress rapidly regulates brain 3beta-HSD activity in a sex-specific manner. To elucidate endocrine regulation of brain 3beta-HSD, we asked whether 17beta-estradiol (E(2)) regulates DHEA metabolism in adult zebra finch (Taeniopygia guttata) and whether there are sex-specific effects. Brain tissue was homogenized and centrifuged to obtain supernatant lacking whole cells and cell nuclei. Supernatant was incubated with [(3)H]DHEA and radioinert E(2)in vitro. Within only 10 min, E(2) significantly reduced 3beta-HSD activity in both male and female brain. Interestingly, the rapid effects of E(2) were more pronounced in females than males. These are the first data to show a rapid effect of estrogens on the songbird brain and suggest that rapid estrogen effects differ between male and female brains.
authors.affiliation: Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada. pradhan@zoology.ubc.ca
authors.forename: Devaleena S
authors.initials: DS
authors.lastname: Pradhan
authors.forename: Yan
authors.initials: Y
authors.lastname: Yu
authors.forename: Kiran K
authors.initials: KK
authors.lastname: Soma
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002855:Chromatography, Thin Layer / Q000379:methods; D003687:Dehydroepiandrosterone / Q000378:metabolism*; D013196:Dihydrotestosterone / Q000031:analogs & derivatives / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D046369:Finches / Q000033:anatomy & histology*; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism; D011375:Progesterone Reductase / Q000378:metabolism; D012727:Sex Characteristics; D013251:Steroid Isomerases / Q000378:metabolism; D013997:Time Factors
chemical_list: C021425:3 beta-hydroxysteroid oxidoreductase-delta(5) 3-ketosteroid isomerase; D004791:Enzyme Inhibitors; D004967:Estrogens; D009097:Multienzyme Complexes; D013196:Dihydrotestosterone; C074283:estradiol 3-benzoate; D003687:Dehydroepiandrosterone; D004958:Estradiol; D011375:Progesterone Reductase; D013251:Steroid Isomerases; C009954:trilostane