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The effects of estrogen on the α2-adrenergic receptor subtypes in rat uterine function in late pregnancy in vitro.
- Source :
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Croatian medical journal [Croat Med J] 2016 Apr 23; Vol. 57 (2), pp. 100-9. - Publication Year :
- 2016
-
Abstract
- Aim: To assess the effect of 17β-estradiol pretreatment on the function and expression of α2- adrenergic receptors (ARs) subtypes in late pregnancy in rats.<br />Methods: Sprague-Dawley rats (n=37) were treated with 17β-estradiol for 4 days starting from the 18th day of pregnancy. The myometrial expression of the α2-AR subtypes was determined by real time polymerase chain reaction and Western blot analysis. In vitro contractions were stimulated with (-)-noradrenaline, and its effect was modified with the selective antagonists BRL 44408 (α2A), ARC 239 (α2B/C), and spiroxatrine (α2A). The cyclic adenosine monophosphate (cAMP) accumulation was also measured. The activated G-protein level was investigated by guanosine 5'-O-[gamma-thio]triphosphate (GTPγS) binding assay.<br />Results: 17β-estradiol pretreatment decreased the contractile effect of (-)-noradrenaline via the α2-ARs, and abolished the contractile effect via the α2B-ARs. All the α2-AR subtypes' mRNA was significantly decreased. 17β-estradiol pretreatment significantly increased the myometrial cAMP level in the presence of BRL 44408 (P=0.001), ARC 239 (P=0.007), and spiroxatrine (P=0.045), but did not modify it in the presence of spiroxatrine + BRL 44408 combination (P=0.073). It also inhibited the G-protein-activating effect of (-)-noradrenaline by 25% in the presence of BRL 44408 + spiroxatrine combination.<br />Conclusions: The expression of the α2-AR subtypes is sensitive to 17β-estradiol, which decreases the contractile response of (-)-noradrenaline via the α2B-AR subtype, and might cause changes in G-protein signaling pathway. Estrogen dysregulation may be responsible for preterm labor or uterine inertia via the α2-ARs.
Details
- Language :
- English
- ISSN :
- 1332-8166
- Volume :
- 57
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Croatian medical journal
- Publication Type :
- Academic Journal
- Accession number :
- 27106352
- Full Text :
- https://doi.org/10.3325/cmj.2016.57.100