title: Expression of calbindin-D28k and its regulation by estrogen in the human endometrium during the menstrual cycle.
abstract: Human endometrium resists embryo implantation except during the 'window of receptivity'. A change in endometrial gene expression is required for the development of receptivity. Uterine calbindin-D28k (CaBP-28k) is involved in the regulation of endometrial receptivity by intracellular Ca2+. Currently, this protein is known to be mainly expressed in brain, kidneys, and pancreas, but potential role(s) of CaBP-28k in the human uterus during the menstrual cycle remain to be clarified. Thus, in this study we demonstrated the expression of CaBP-28k in the human endometrium in distinct menstrual phases. During the human menstrual cycle, uterine expression levels of CaBP-28k mRNA and protein increased in the proliferative phase and fluctuated in these tissues, compared with that observed in other phases. We assessed the effects of two sex-steroid hormones, 17beta-estradiol (E2) and progesterone (P4), on the expression of CaBP-28k in Ishikawa cells. A significant increase in the expression of CaBP-28k mRNA was observed at the concentrations of E2 (10(-9 to -7) M). In addition, spatial expression of CaBP-28k protein was detected by immunohistochemistry. CaBP-28k was abundantly localized in the cytoplasm of the luminal and glandular epithelial cells during the proliferative phases (early-, mid-, late-) and early-secretory phase of menstrual cycle. Taken together, these results indicate that CaBP-28k, a uterine calcium binding protein, is abundantly expressed in the human endometrium, suggesting that uterine expression of CaBP-28k may be involved in reproductive function during the human menstrual cycle.
authors.affiliation: Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea.
authors.forename: Hyun
authors.initials: H
authors.lastname: Yang
authors.forename: Tae-Hee
authors.initials: TH
authors.lastname: Kim
authors.forename: Hae-Hyeog
authors.initials: HH
authors.lastname: Lee
authors.forename: Kyung-Chul
authors.initials: KC
authors.lastname: Choi
authors.forename: Yeon-Pyo
authors.initials: YP
authors.lastname: Hong
authors.forename: Peter Ck
authors.initials: PC
authors.lastname: Leung
authors.forename: Eui-Bae
authors.initials: EB
authors.lastname: Jeung
mesh_terms: D000328:Adult; D064092:Calbindin 1; D064026:Calbindins; D004717:Endometrium / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008597:Menstrual Cycle / Q000187:drug effects / Q000502:physiology*; D008875:Middle Aged; D011374:Progesterone / Q000494:pharmacology; D064030:S100 Calcium Binding Protein G / Q000096:biosynthesis*
chemical_list: C576498:CALB1 protein, human; D064092:Calbindin 1; D064026:Calbindins; D004967:Estrogens; D064030:S100 Calcium Binding Protein G; D011374:Progesterone; D004958:Estradiol