Linked Life Data

15985637

Source:http://linkedlifedata.com/resource/pubmed/id/15985637

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2005-6-29
pubmed:abstractText
The effectiveness of beta2-agonists in preterm delivery is reduced by several factors. The aim of this study was to determine the influence of late pregnancy in the uterus-relaxing effect of terbutaline in the rat in vitro. Rat uterine tissues from late pregnancy (days 15, 18, 20 and 22) were used. In vitro electrical field-stimulation (EFS) was used to evoke contractions. The radioligand-binding technique, reverse transcription-polymerase chain reaction and radioimmunoassay technique were used to determine the beta-adrenergic receptor density and mRNA level and the plasma sex hormone level, respectively. The activated G-protein level of the beta-adrenergic receptors was investigated by a radiolabelled GTP binding assay.EFS-induced contractions were inhibited by terbutaline. This effect decreased towards term with respect to both the EC50 and maximal inhibition values. A drop in plasma progesterone level was also detected. Binding studies revealed an increase in beta-adrenergic receptor number on the last day of pregnancy, which correlated with the change in receptor mRNA level. The G-protein-activating effect of terbutaline decreased continuously between days 15 and 20. Surprisingly, terbutaline decreased the G-protein activation to below the basal level on day 22. However, progesterone pretreatment set back the uterine action of terbutaline, increased the density of the beta2-adrenergic receptors and their mRNA level and increased the G-protein-activating property of terbutaline. These data provide evidence of a pregnancy-induced decrease in activated G-protein level after beta2-agonist stimulation. The decrease in plasma progesterone level has a crucial role in this process. The effects of beta2-adrenergic receptor agonists in tocolytic therapy may possibly be potentiated with progesterone.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1470-1626
pubmed:author
pubmed:issnType
Print
pubmed:volume
130
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
113-22
pubmed:dateRevised
2009-11-3
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Pregnancy-induced decrease in the relaxant effect of terbutaline in the late-pregnant rat myometrium: role of G-protein activation and progesterone.
pubmed:affiliation
Department of Pharmacodynamics and Biopharmacy, Faculty of Pharmacy, University of Szeged, H-6720 Szeged, Eötvös u. 6, Hungary.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't