title: c-fos and estrogen receptor gene expression pattern in the rat uterine epithelium during the estrous cycle.
abstract: Different studies in ovariectomized estrogen treated animals support the idea that c-fos plays a role in the proliferation of uterine epithelial cells. However, these studies invite us to reassess the role played by c-fos in epithelial cell types of the endometrium during the estrous cycle. The present study was undertaken to determine the c-fos and estrogen receptor (ER) gene expression pattern in the rat uterine epithelium during the estrous cycle in which natural and cyclic changes of steroid hormones occur, and correlate these changes with the proliferation status of this cellular types. Proliferation was assessed during the estrous cycle using bromodeoxyuridine incorporation to DNA. ERalpha and beta proteins were assessed by immunohistochemistry. The regulation of c-fos gene expression in the uterus of intact animals during the estrous cycle was evaluated using both in situ hybridization and immunohistochemistry. Estradiol (E(2)) and progesterone (P(4)) plasma levels were assessed by radioimmunoassay. The results indicated that luminal (LE) and glandular epithelia (GE) presented maximal proliferation during the metestrus (M) and the diestrus (D) days. However, during the proestrus (P) day only LE presented proliferation, and during the estrus (E) day only the stromal cells proliferated. A marked immunostaining for ERalpha was detected in both LE and GE cells during the early phases of the cycle but diminished on the P and the E day. In contrast, ERbeta was undetectable in both epithelia during all stages of the cycle. The highest c-fos mRNA level was detected in both epithelia on the M day, followed by a significant reduction during the other days of the cycle. The highest protein content was observed on the M and D days, and the minimal value was detected on the E day. The c-Fos protein level in LE was increased during M and D days, presenting a high correlation with the cellular proliferation pattern of this cell type. In conclusion, the overall results indicate that c-Fos protein presented a good correlation with uterine epithelial cell proliferation of LE. In the case of GE, the same tendency was observed, although no significant correlation was found. Both in LE and GE, c-fos mRNA did not strictly correlate with its protein levels. c-fos seems to have a postranscriptional regulation in uterine epithelial cells during the rat's estrous cycle.
authors.affiliation: Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacan 04510, México, D.F., México.
authors.forename: C Adriana
authors.initials: CA
authors.lastname: Mendoza-Rodríguez
authors.forename: Horacio
authors.initials: H
authors.lastname: Merchant-Larios
authors.forename: Maria L
authors.initials: ML
authors.lastname: Segura-Valdez
authors.forename: Norma
authors.initials: N
authors.lastname: Moreno-Mendoza
authors.forename: María E
authors.initials: ME
authors.lastname: Cruz
authors.forename: Paola
authors.initials: P
authors.lastname: Arteaga-López
authors.forename: Ignacio
authors.initials: I
authors.lastname: Camacho-Arroyo
authors.forename: Roberto
authors.initials: R
authors.lastname: Domínguez
authors.forename: Marco
authors.initials: M
authors.lastname: Cerbón
mesh_terms: D000818:Animals; D002455:Cell Division / Q000502:physiology; D004848:Epithelium / Q000378:metabolism; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D030762:Estrous Cycle / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics*; D011863:Radioimmunoassay; D051381:Rats; D020318:Rats, Long-Evans; D011960:Receptors, Estrogen / Q000235:genetics* / Q000276:immunology; D014599:Uterus / Q000378:metabolism*
chemical_list: D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D016760:Proto-Oncogene Proteins c-fos; D011960:Receptors, Estrogen