Weiss, J. M. and Polack, S. and Treeck, O. and Diedrich, K. and Ortmann, O. (2006) Regulation of GnRH I receptor gene expression by the GnRH agonist triptorelin, estradiol, and progesterone in the gonadotroph-derived cell line alpha T3-1. ENDOCRINE, 30 (1). pp. 139-144. ISSN 1355-008X, 1559-0100
Full text not available from this repository. (Request a copy)Abstract
GnRH receptor (GnRH-R) concentration are modulated by ovarian steroids and GnRH. To elucidate whether this regulation is due to alterations at the transcriptional level, we examined the GnRH I-R mRNA expression in the gonadotroph-derived cell line alpha T3-1 treated with different estradiol and progesterone paradigms and the GnRH I agonist triptorelin. aT3-1 cells were treated with different steroid paradigms: 1 nM estradiol or 100 nM progesterone for 48 h alone or in combination. Cells were expose to 10 nM or 100 pM triptorelin for 30 min, 3 h, 9 h, or, in pulsatile way, with a 5-min pulse per hour. The GnRH I-R mRNA was determined by Northern blot analysis. GnRH I-R mRNA from cells treated with continuous triptorelin decreased in a time- and concentration-dependent manner. Pulsatile triptorelin increased GnRH I-R gene expression. Progesterone alone further enhanced this effect, whereas estradiol and its combination with progesterone diminished it. Continuous combined treatment with estradiol and progesterone lead to a significant decrease of GnRH I-R mRNA by 30% and by 35% for estradiol alone. The addition of 10 nM triptorelin for 30 min or 3 h could not influence that steroid effect. In conclusion, estradiol and progesterone exclusively decreased GnRH I-R mRNA in alpha T3-1 cells no matter whether they are treated additionally with the GnRH I agonist triptorelin. The enhance sensitivity of gonadotrophs and GnRH I-R upregulation by estradiol is not due to increased GnRH I gene expression because GnRH I-R mRNA is downregulated by estradiol and progesterone. Other pathways of the GnRH I-R signal transduction might be involved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | MESSENGER-RIBONUCLEIC-ACID; LHRH ANTAGONIST CETRORELIX; HOMOLOGOUS UP-REGULATION; RAT PITUITARY-CELLS; HORMONE RECEPTOR; LUTEINIZING-HORMONE; RNA LEVELS; ORCHIECTOMIZED SHEEP; DOWN-REGULATION; TISSUE; GnRH receptor; GnRH agonist; estradiol; progesterone; alpha T3-1 cells |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Frauenheilkunde und Geburtshilfe (Schwerpunkt Frauenheilkunde) |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 09 Feb 2021 05:46 |
| Last Modified: | 09 Feb 2021 05:46 |
| URI: | https://pred.uni-regensburg.de/id/eprint/34199 |
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