title: Induction and subcellular redistribution of progesterone receptor A and B by tamoxifen in the hypothalamic ventromedial neurons of young adult female Wistar rats.
abstract: The ventrolateral division of the hypothalamic ventromedial nucleus (VMNvl) is a brain center for estrogen-dependent triggering of female sexual behavior upon progesterone receptor (PR) activation. We examined the agonistic and antagonistic actions of tamoxifen in this nucleus by analyzing its effects on the total number of PR-immunoreactive neurons, PR mRNA and protein levels, and subcellular location of PRs in ovariectomized Wistar rats. The results show that tamoxifen has no agonistic action in the number of PR-immunoreactive neurons, but increases PR expression and labeling in the nucleus and cytoplasm of VMNvl neurons that constitutively express PRs. As an antagonist, tamoxifen partially inhibited the estradiol-dependent increase in the number of PR-immunoreactive neurons and in PR mRNA and protein levels, without interfering with the subcellular location of the protein. We suggest that tamoxifen influence on PR expression in the VMNvl critically depends on the presence or absence of estradiol.
authors.affiliation: Department of Anatomy, Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; CINTESIS, Centro de Investigação em Tecnologias e Serviços de Saúde Faculty of Medicine, University of Porto, Rua Dr. Plácido da Costa, 4200-450 Porto, Portugal. Electronic address: sasusana@med.up.pt.
authors.forename: Susana I
authors.initials: SI
authors.lastname: Sá
authors.affiliation: UCIBIO, REQUIMTE, Laboratory of Biochemistry, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, n° 228, 4050-313 Porto, Portugal. Electronic address: brunofonseca@ff.up.pt.
authors.forename: Bruno M
authors.initials: BM
authors.lastname: Fonseca
authors.affiliation: UCIBIO, REQUIMTE, Laboratory of Biochemistry, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, n° 228, 4050-313 Porto, Portugal. Electronic address: natercia@ff.up.pt.
authors.forename: Natércia
authors.initials: N
authors.lastname: Teixeira
authors.affiliation: Department of Anatomy, Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; CINTESIS, Centro de Investigação em Tecnologias e Serviços de Saúde Faculty of Medicine, University of Porto, Rua Dr. Plácido da Costa, 4200-450 Porto, Portugal. Electronic address: madeira@med.up.pt.
authors.forename: M Dulce
authors.initials: MD
authors.lastname: Madeira
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002452:Cell Count; D004958:Estradiol / Q000097:blood; D005260:Female; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D011374:Progesterone / Q000097:blood; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D011980:Receptors, Progesterone / Q000235:genetics / Q000378:metabolism*; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D013629:Tamoxifen / Q000494:pharmacology*; D014599:Uterus / Q000187:drug effects; D014697:Ventromedial Hypothalamic Nucleus / Q000166:cytology*
chemical_list: D012333:RNA, Messenger; D011980:Receptors, Progesterone; C101118:progesterone receptor A; C097314:progesterone receptor B; D013629:Tamoxifen; D011374:Progesterone; D004958:Estradiol
keywords: Estrogen receptor; Hypothalamic ventromedial nucleus; Progesterone receptor; Stereology; Tamoxifen; Western blot