title: Expression of cellular retinol- and cellular retinoic acid-binding proteins in the rat cervical epithelium is regulated by endocrine stimuli during normal squamous metaplasia.
abstract: To determine the potential roles of retinoids in the growth and differentiation of the reproductive tract epithelium, we have studied the expression of the cellular retinol- and retinoic acid-binding proteins, CRBP I and CRABP I, in the reproductive tract of female rats. CRBP I and CRABP I gene expression have been examined in the oviduct, ovary, uterus, and particularly in the cervix, which normally undergoes a cyclical squamous metaplasia during the estrus cycle. CRBP I was expressed in all four tissues examined, whereas CRABP I was expressed predominantly in cervix and uterus. In the cervix, CRBP I was detected in all epithelial layers including the columnar epithelium but was greatly reduced in the superficial, cornified layers of the stratified squamous epithelium. CRABP I was localized to the basement membrane region of the epithelium with the strongest expression in the basal layer of epithelial cells. While the expression of CRBP I and CRABP I in the keratinizing exocervix changed during the estrus cycle, it remained constant in the incompletely keratinized endocervix. The highest levels of CRBP I were seen during anestrus and proestrus, and for CRABP I during proestrus. Both CRBP I and CRABP I levels fell to barely detectable levels during estrus and metestrus. Using estrogen repletion of ovariectomized rats, we found that CRABP I levels transiently increased during the early proliferative response to estrogen, whereas CRBP I levels gradually declined, becoming barely detectable by 24 to 48 hours. These results suggest that CRBP I and CRABP I play different roles in the cyclical squamous metaplasia normally occurring in this tissue and that hormonal control of CRBP I and CRABP I expression might modulate the retinoid responsiveness of the epithelium during this process.
authors.affiliation: Institute of Human Nutrition, Columbia University, New York, New York 10032.
authors.forename: L
authors.initials: L
authors.lastname: Tannous-Khuri
authors.forename: P
authors.initials: P
authors.lastname: Hillemanns
authors.forename: N
authors.initials: N
authors.lastname: Rajan
authors.forename: T C
authors.initials: TC
authors.lastname: Wright
authors.forename: D A
authors.initials: DA
authors.lastname: Talmage
mesh_terms: D000818:Animals; D002584:Cervix Uteri / Q000378:metabolism* / Q000473:pathology; D004702:Endocrine Glands / Q000502:physiology*; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D004971:Estrus; D005260:Female; D008679:Metaplasia; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D018168:Receptors, Retinoic Acid / Q000235:genetics / Q000378:metabolism*; D012016:Reference Values; D012177:Retinol-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D054840:Retinol-Binding Proteins, Cellular; D014018:Tissue Distribution
chemical_list: D012333:RNA, Messenger; D018168:Receptors, Retinoic Acid; D012177:Retinol-Binding Proteins; D054840:Retinol-Binding Proteins, Cellular