Non-genomic uterorelaxant actions of corticosteroid hormones in rats: An in vitro and in vivo study
We aimed to identify the short-term effects of a glucocorticoid (GC) and a mineralocorticoid (MC) on non-pregnant and late pregnant rat uterine contractions to estimate their tocolytic potential. The in vitro contractility studies were performed with uterine tissues from non-pregnant and 22-day preg...
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Veröffentlicht in: | European journal of pharmacology 2022-11, Vol.935, p.175346-175346, Article 175346 |
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Zusammenfassung: | We aimed to identify the short-term effects of a glucocorticoid (GC) and a mineralocorticoid (MC) on non-pregnant and late pregnant rat uterine contractions to estimate their tocolytic potential.
The in vitro contractility studies were performed with uterine tissues from non-pregnant and 22-day pregnant SPRD rats. The cumulative dose-response of fludrocortisone (FLU) and dexamethasone (DEX) was measured alone or in the presence of steroid receptor antagonist mifepristone (MIF) or spironolactone (SPR). [35S]GTPγS and cAMP immunoassays were carried out to detect the activated G-proteins and cAMP, respectively. The in vivo uterine action of single doses of FLU and DEX was measured by smooth muscle electromyography. The results were statistically analyzed with an unpaired t-test.
FLU and DEX relaxed both pregnant (33 and 34%) and non-pregnant (37 and 34%) uteri in vitro. MIF inhibited the relaxing effect of DEX, especially in the pregnant uterus, but reduced the effect of FLD only in non-pregnant tissues. GTPγS studies showed a MIF-sensitive elevation in activated G-proteins both in pregnant and non-pregnant uteri by DEX, whereas FLU induced activation only in non-pregnant samples. DEX relaxed pregnant and non-pregnant uteri in vivo in a MIF-sensitive way.
DEX can inhibit contractions in the late pregnant uterus in a non-genomic manner, while FLU seems to be ineffective. Its action is mediated by a G-protein-coupled receptor that can be blocked by mifepristone. Further investigations are necessary to determine the required dose and duration of GCs in the therapy of premature birth. |
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ISSN: | 0014-2999 1879-0712 |
DOI: | 10.1016/j.ejphar.2022.175346 |