title: Pituitary galaninergic system activity in female rats: the regulatory role of gonadal steroids.
abstract: The well-recognized sensitivity of the galanin gene in the anterior pituitary gland to estrogen suggests that estrogen receptor activity may influence the galaninergic system through modulation of galanin receptor (GALR) gene expression. Here, we evaluated the following: (i) the effects of estrogen on GALR mRNA expression; (ii) the estrogen receptor subtype that is specifically involved in this activity; and (iii) the effects of progesterone in the absence or presence of estrogen on galanin concentration in anterior pituitary gland. In the first experiment, ovariectomized 4-month-old rats were pre-treated subcutaneously with 17β-estradiol (3 x 20 μg), the ESR1 (ERα) agonist propyl pyrazole triol (PPT) (3 x 5 mg), and the ESR2 (ERβ) agonist diarylpropionitrile (DPN) (3 x 0.5 mg). In the second experiment, 4-month-old ovariectomized females received daily subcutaneous injections of 17β-estradiol (3 x 20 μg), progesterone (2 x 5 mg), or combined estradiol (3 x 20 μg) and progesterone (2 x 5 mg). Anterior pituitaries were excised the day after the final 17β-estradiol injection (experiment I) and 1 hour after receiving the second progesterone dose. Relative GALR1, GALR2, and GALR3 mRNA expression was evaluated using quantitative real-time PCR, and pituitary galanin concentration was determined using a specific radioimmunoassay. The results revealed that estrogen predominantly induced a 5-fold increase in GALR3 gene transcription. To a lesser extent, 17β-estradiol also increased GALR1 mRNA expression, but had no effect on GALR2 mRNA levels. The estrogen-induced increase in GALR3 gene expression occurred exclusively through ESR1 activation. The increase in GALR1 gene expression occurred through activation of both estrogen receptor subtypes, but the ESR2 subtype was predominantly involved. Furthermore, the results revealed that progesterone regulates the activity of the pituitary galaninergic system by facilitating estradiol-induced galanin synthesis in the female rat anterior pituitary gland.
authors: Department of Neuroendocrinology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jablonna n. Warsaw, Poland. a.gajewska@ifzz.pl.
authors: A
authors: A
authors: Gajewska
authors: Department of Neuroendocrinology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jablonna n. Warsaw, Poland.
authors: M
authors: M
authors: Zielinska-Gorska
authors: Neuroendocrinology Department, Medical Centre for Postgraduate Education, Warsaw, Poland.
authors: E
authors: E
authors: Wasilewska-Dziubinska
authors: Department of Neuroendocrinology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jablonna n. Warsaw, Poland.
authors: M
authors: M
authors: Baran
authors: Department of Neuroendocrinology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jablonna n. Warsaw, Poland.
authors: G
authors: G
authors: Kotarba
authors: Department of Endocrinology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jablonna n. Warsaw, Poland;
authors: K
authors: K
authors: Gorski
mesh_terms: D000818:Animals; D004958:Estradiol / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000819:agonists; D047629:Estrogen Receptor beta / Q000819:agonists; D005260:Female; D019004:Galanin / Q000235:genetics*; D009570:Nitriles / Q000494:pharmacology; D010052:Ovariectomy; D010636:Phenols / Q000494:pharmacology; D010902:Pituitary Gland / Q000187:drug effects* / Q000378:metabolism; D011374:Progesterone / Q000494:pharmacology*; D011422:Propionates / Q000494:pharmacology; D011498:Protein Precursors / Q000235:genetics*; D011720:Pyrazoles / Q000494:pharmacology; D017208:Rats, Wistar; D044088:Receptors, Galanin / Q000235:genetics*
chemical_list: C486182:2,3-bis(4-hydroxyphenyl)-propionitrile; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; C489169:Gal protein, rat; D009570:Nitriles; D010636:Phenols; D011422:Propionates; D011498:Protein Precursors; D011720:Pyrazoles; D044088:Receptors, Galanin; C486184:4,4',4''-(4-propyl-((1)H)-pyrazole-1,3,5-triyl) tris-phenol; D011374:Progesterone; D004958:Estradiol; D019004:Galanin