title: Estrogen regulation of duodenal bicarbonate secretion and sex-specific protection of human duodenum.
abstract: OBJECTIVE
  The reason that women have a lower prevalence of duodenal ulcer is not clear. We investigated whether estrogen regulates human duodenal bicarbonate secretion (DBS) and whether this process accounts for sex differences in the prevalence of duodenal ulcer.
  
  
  METHODS
  We performed an epidemiologic study to correlate duodenal ulcer prevalence with sex and age. Proximal DBS was measured from healthy subjects. Estrogen-receptor expression was examined in human duodenal mucosa by immunoblot and immunohistochemical analyses.
  
  
  RESULTS
  Among women, the prevalence of duodenal ulcer was significantly lower than among men. The reduced prevalence was greatest among premenopausal women (20-49 y), who were 3.91- to 5.09-fold less likely to develop duodenal ulcers than age-matched men; the difference was reduced to 1.32-fold or less among subjects aged 60 years or older. Premenopausal (20-29 y), but not postmenopausal (60-69 y), women had significantly higher basal and acid-stimulated DBS than the age-matched men. Basal and acid-stimulated DBS in premenopausal women (20-29 y) were significantly higher than in postmenopausal women (60-69 y), whereas there were no significant differences in basal or acid-stimulated DBS between men who were aged 20-29 years or 60-69 years. Serum levels of estradiol changed in parallel with basal and acid-stimulated DBS during the physiological menstrual cycle in premenopausal women. 17β-estradiol-stimulated DBS was independent of age or sex. Estrogen receptors α and β were detected on plasma membranes and in the cytosol of human duodenal epithelial cells.
  
  
  CONCLUSIONS
  Estrogen regulates human DBS, which could reduce the risk for duodenal ulcer in women and contribute to sex differences in the prevalence of duodenal ulcer.
authors.affiliation: Department of Gastroenterology, Affiliated Hospital, Zunyi Medical College, Zunyi, China. tuobiguang@yahoo.com.cn
authors.forename: Biguang
authors.initials: B
authors.lastname: Tuo
authors.forename: Guorong
authors.initials: G
authors.lastname: Wen
authors.forename: Jinqi
authors.initials: J
authors.lastname: Wei
authors.forename: Xuemei
authors.initials: X
authors.lastname: Liu
authors.forename: Xue
authors.initials: X
authors.lastname: Wang
authors.forename: Yalin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Huichao
authors.initials: H
authors.lastname: Wu
authors.forename: Xiao
authors.initials: X
authors.lastname: Dong
authors.forename: Jimmy Y C
authors.initials: JY
authors.lastname: Chow
authors.forename: Volker
authors.initials: V
authors.lastname: Vallon
authors.forename: Hui
authors.initials: H
authors.lastname: Dong
mesh_terms: D000328:Adult; D000368:Aged; D001639:Bicarbonates / Q000378:metabolism*; D002681:China / Q000453:epidemiology; D004381:Duodenal Ulcer / Q000453:epidemiology* / Q000208:ethnology / Q000378:metabolism; D004386:Duodenum / Q000378:metabolism*; D047628:Estrogen Receptor alpha / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000378:metabolism; D004967:Estrogens / Q000378:metabolism*; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D017698:Postmenopause / Q000378:metabolism; D015995:Prevalence; D012307:Risk Factors; D012727:Sex Characteristics
chemical_list: D001639:Bicarbonates; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens