title: In vivo oestrogenic modulation of Egr1 and Pitx1 gene expression in female rat pituitary gland.
abstract: EGR1 and PITX1 are transcription factors required for gonadotroph cell Lhb promoter activation. To determine changes in Egr1 and Pitx1 mRNA levels in central and peripheral pituitary stimulations, an in vivo model based on i.c.v. pulsatile (1 pulse/0.5 h over 2 h) GnRH agonist (1.5 nM buserelin) or antagonist (2 nM antide) microinjections was used. The microinjections were given to ovariectomised and 17β-oestradiol (E2) (3×20 μg), ERA (ESR1) agonist propyl pyrazole triol (PPT) (3×0.5 mg), ERB (ESR2) agonist diarylpropionitrile (DPN) (3×0.5 mg) s.c. pre-treated rats 30 min after last pulse anterior pituitaries were excised. Relative mRNA expression was determined by quantitative RT-PCR (qRT-PCR). Results revealed a gene-specific response for GnRH and/or oestrogenic stimulations in vivo. Buserelin pulses enhanced Egr1 expression by 66% in ovariectomised rats, whereas the oestradiol-supplemented+i.c.v. NaCl-microinjected group showed a 50% increase in Egr1 mRNA expression. The oestrogenic signal was transmitted via ERA (ESR1) and ERB (ESR2) activation as administration of PPT and DPN resulted in 97 and 62%, respectively, elevation in Egr1 mRNA expression. A synergistic action of GnRH agonist and 17β-oestradiol (E2) stimulation of the Egr1 gene transcription in vivo were found. GnRHR activity did not affect Pitx1 mRNA expression; regardless of NaCl, buserelin or antide i.c.v. pulses, s.c. oestrogenic supplementation (with E2, PPT or DPN) consistently decreased (by -46, -48 and -41% respectively) the Pitx1 mRNA in the anterior pituitary gland. Orchestrated Egr1 and Pitx1 activities depending on specific central and peripheral regulatory inputs could be responsible for physiologically variable Lhb gene promoter activation in vivo.
authors.affiliation: Department of NeuroendocrinologyThe Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka Street 3, 05-110 Jablonna n. Warsaw, PolandNeuroendocrinology DepartmentMedical Centre for Postgraduate Education, Marymoncka 99/103 Street, 01-813 Warsaw, PolandDepartment of Molecular BiologyInstitute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzebiec, 05-552 Magdalenka, Poland a.gajewska@ifzz.pan.pl.
authors.forename: Alina
authors.initials: A
authors.lastname: Gajewska
authors.affiliation: Department of NeuroendocrinologyThe Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka Street 3, 05-110 Jablonna n. Warsaw, PolandNeuroendocrinology DepartmentMedical Centre for Postgraduate Education, Marymoncka 99/103 Street, 01-813 Warsaw, PolandDepartment of Molecular BiologyInstitute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzebiec, 05-552 Magdalenka, Poland.
authors.forename: Andrzej P
authors.initials: AP
authors.lastname: Herman
authors.affiliation: Department of NeuroendocrinologyThe Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka Street 3, 05-110 Jablonna n. Warsaw, PolandNeuroendocrinology DepartmentMedical Centre for Postgraduate Education, Marymoncka 99/103 Street, 01-813 Warsaw, PolandDepartment of Molecular BiologyInstitute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzebiec, 05-552 Magdalenka, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Wolińska-Witort
authors.affiliation: Department of NeuroendocrinologyThe Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka Street 3, 05-110 Jablonna n. Warsaw, PolandNeuroendocrinology DepartmentMedical Centre for Postgraduate Education, Marymoncka 99/103 Street, 01-813 Warsaw, PolandDepartment of Molecular BiologyInstitute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzebiec, 05-552 Magdalenka, Poland.
authors.forename: Kazimierz
authors.initials: K
authors.lastname: Kochman
authors.affiliation: Department of NeuroendocrinologyThe Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka Street 3, 05-110 Jablonna n. Warsaw, PolandNeuroendocrinology DepartmentMedical Centre for Postgraduate Education, Marymoncka 99/103 Street, 01-813 Warsaw, PolandDepartment of Molecular BiologyInstitute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzebiec, 05-552 Magdalenka, Poland.
authors.forename: Lech
authors.initials: L
authors.lastname: Zwierzchowski
mesh_terms: D000818:Animals; D051766:Early Growth Response Protein 1 / Q000235:genetics* / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology* / Q000502:physiology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D007986:Luteinizing Hormone / Q000097:blood; D037101:Luteinizing Hormone, beta Subunit / Q000235:genetics* / Q000378:metabolism; D051761:Paired Box Transcription Factors / Q000235:genetics* / Q000378:metabolism; D010902:Pituitary Gland / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D037101:Luteinizing Hormone, beta Subunit; D051761:Paired Box Transcription Factors; C101485:homeobox protein PITX1; D004958:Estradiol; D007986:Luteinizing Hormone
keywords: Egr1; Pitx1; gene expression; oestrogenic modulation; rat pituitary gland