Document Detail


Progesterone enhances the tocolytic effect of ritodrine in isolated pregnant human myometrium.
MedLine Citation:
PMID:  15695987     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: To evaluate the effect of natural progesterone on the relaxant effect of ritodrine on pregnant human oxytocin-induced myometrial contractility.
STUDY DESIGN: Isometric tension recordings were performed under physiologic conditions on isolated myometrial strips taken from low-risk term pregnant women undergoing elective cesarean section. Cumulative effects of natural progesterone (10 (-11) to 10 (-5) mol/L) on oxytocin-induced myometrial contractility were evaluated. Contractile activity following ritodrine exposure was also investigated in myometrium pretreated with natural progesterone.
RESULTS: Natural progesterone alone exerted a concentration-dependent relaxant effect on myometrial contractions. The concentration-response curve for ritodrine from natural progesterone pretreated myometrium was shifted to the left with a significant reduction ( P < .01) of 50% of the maximal response, contraction amplitude ( P < .05), and frequency ( P < .05). However, there was no significant difference in the mean maximal inhibition achieved ( P = .95).
CONCLUSION: Natural progesterone increased the relaxant effect of ritodrine by reducing 50% of the maximal response, amplitude, and frequency of myometrial contraction, most likely through nongenomic actions. These results suggest that natural progesterone may be beneficial for preventing preterm birth in a low-risk population.
Authors:
Boonsri Chanrachakul; Fiona Broughton Pipkin; Averil Y Warren; Sabaratnam Arulkumaran; Raheela N Khan
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  American journal of obstetrics and gynecology     Volume:  192     ISSN:  0002-9378     ISO Abbreviation:  Am. J. Obstet. Gynecol.     Publication Date:  2005 Feb 
Date Detail:
Created Date:  2005-02-07     Completed Date:  2005-03-10     Revised Date:  2010-12-30    
Medline Journal Info:
Nlm Unique ID:  0370476     Medline TA:  Am J Obstet Gynecol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  458-63     Citation Subset:  AIM; IM    
Affiliation:
Academic Division of Obstetrics and Gynaecology, Derby City General Hospital, University of Nottingham, Derby, DE22 3DT, United Kingdom.
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MeSH Terms
Descriptor/Qualifier:
Adrenergic beta-Agonists / pharmacology*
Dose-Response Relationship, Drug
Drug Synergism
Female
Humans
Muscle Relaxation / drug effects
Myometrium / drug effects*
Pregnancy
Progesterone / pharmacology*
Receptors, Adrenergic, beta-2 / physiology
Ritodrine / pharmacology*
Tocolytic Agents / pharmacology*
Chemical
Reg. No./Substance:
0/Adrenergic beta-Agonists; 0/Receptors, Adrenergic, beta-2; 0/Tocolytic Agents; 26652-09-5/Ritodrine; 57-83-0/Progesterone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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