title: Gender-specific protection of estrogen against gastric acid-induced duodenal injury: stimulation of duodenal mucosal bicarbonate secretion.
abstract: Because human duodenal mucosal bicarbonate secretion (DMBS) protects duodenum against acid-peptic injury, we hypothesize that estrogen stimulates DMBS, thereby attributing to the clinically observed lower incidence of duodenal ulcer in premenopausal women than the age-matched men. We found that basal and acid-stimulated DMBS responses were 1.5 and 2.4-fold higher in female than male mice in vivo, respectively. Acid-stimulated DMBS in both genders was abolished by ICI 182,780 and tamoxifen. Estradiol-17beta (E2) and the selective estrogen receptor (ER) agonists of ERalpha [1,3,5-Tris(4-hydroxyphenyl)-4-propyl-1H-pyrazole] and ERbeta [2,3-bis(4-hydroxyphenyl) propionitrile], but not progesterone, rapidly stimulated ER-dependent murine DMBS in vivo. E2 dose dependently stimulated murine DMBS, which was attenuated by a Cl(-)/HCO3(-) anion exchanger inhibitor 4,4'-didsothio- cyanostilbene-2, 2'-disulfonic acid, removal of extracellular Cl(-), and in cystic fibrosis transmembrane conductance regulator knockout female mice. E2 stimulated murine DMBS in vitro in both genders with significantly greater response in female than male mice (female to male ratio = 4.3). ERalpha and ERbeta mRNAs and proteins were detected in murine duodenal epithelium of both genders; however, neither ERalpha nor ERbeta mRNA and protein expression levels differed according to gender. E2 rapidly mobilized intracellular calcium in a duodenal epithelial SCBN cell line that expresses ERalpha and ERbeta, whereas BAPTA-AM abolished E2-stimulated murine DMBS. Thus, our data show that E2 stimulates DMBS via ER dependent mechanisms linked to intracellular calcium, cystic fibrosis transmembrane conductance regulator, and Cl(-)/HCO3(-) anion exchanger. Gender-associated differences in basal, acid- and E2-stimulated DMBS may have offered a reasonable explanation for the clinically observed lower incidence of duodenal ulcer in premenopausal women than age-matched men.
authors.affiliation: Department of Medicine, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA.
authors.forename: Anders
authors.initials: A
authors.lastname: Smith
authors.forename: Cheyanne
authors.initials: C
authors.lastname: Contreras
authors.forename: Kwang Hyun
authors.initials: KH
authors.lastname: Ko
authors.forename: Jimmy
authors.initials: J
authors.lastname: Chow
authors.forename: Xiao
authors.initials: X
authors.lastname: Dong
authors.forename: Biguang
authors.initials: B
authors.lastname: Tuo
authors.forename: Hong-hai
authors.initials: HH
authors.lastname: Zhang
authors.forename: Dong-bao
authors.initials: DB
authors.lastname: Chen
authors.forename: Hui
authors.initials: H
authors.lastname: Dong
mesh_terms: D000818:Animals; D001639:Bicarbonates / Q000378:metabolism*; D002478:Cells, Cultured; D019610:Cytoprotection / Q000187:drug effects* / Q000502:physiology; D004285:Dogs; D004378:Duodenal Diseases / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D004958:Estradiol / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D004965:Estrogen Antagonists / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D000077267:Fulvestrant; D005744:Gastric Acid / Q000502:physiology*; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011960:Receptors, Estrogen / Q000378:metabolism / Q000502:physiology; D012727:Sex Characteristics; D013629:Tamoxifen / Q000378:metabolism / Q000494:pharmacology
chemical_list: D001639:Bicarbonates; D004965:Estrogen Antagonists; D011960:Receptors, Estrogen; D013629:Tamoxifen; D000077267:Fulvestrant; D004958:Estradiol