title: Sex- and cell-specific expression of an estrogen receptor isoform in the pituitary gland.
abstract: The presence of multiple monomeric forms has been described for the estrogen receptor (ER) in the pituitary gland. We analyzed ER mRNA forms in male and female rat pituitary. A single 6.2-kb ER mRNA species was detected in the male rat pituitary, whereas the female rat pituitary exhibited two ER mRNA forms of 6.2 and 5.5 kb, respectively. The 6.2-kb mRNA was present throughout the different stages of the estrous cycle, while the 5.5-kb mRNA appeared to be restricted to proestrus, suggesting an acute regulation of ER transcription at this stage. The 5.5-kb ER mRNA could be rapidly induced either by 17 beta-estradiol replacement in ovariectomized adult female rats or by priming immature rats with pregnant-mare serum gonadotropin. Using enriched cell populations, an inverse and strong correlation was established between the presence of the 5.5-kb ER mRNA form and the number of gonadotropes. Conversely, the localization of the 5.5-kb mRNA form was demonstrated in lactotrope populations. In order to elucidate the structural modifications in the transiently expressed ER mRNA, a series of reverse-transcriptase polymerase chain reaction amplifications was carried out using several pairs of primers corresponding to the entire ER-coding region. The data showed that no alternative splicing was occurring in the ER-coding region involving a potential role of either 3'- or 5'-untranslated regions. Thus, ER presents a 17 beta-estradiol-dependent transcriptional mechanism triggered on proestrous day and specific to the female lactotropes.
authors.affiliation: Centre National de la Recherche Scientifique, Unité de Recherche Associée 256, Université de Rennes I, France.
authors.forename: F
authors.initials: F
authors.lastname: Demay
authors.forename: C
authors.initials: C
authors.lastname: Tiffoche
authors.forename: M L
authors.initials: ML
authors.lastname: Thieulant
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D005260:Female; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011960:Receptors, Estrogen / Q000378:metabolism*; D017678:Sex Distribution; D012737:Sex Factors
chemical_list: D012333:RNA, Messenger; D011960:Receptors, Estrogen