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Updated: Aug 30, 2026

Contractility Measurements of Human Uterine Smooth Muscle to Aid Drug Development
Published on: January 26, 2018
Bile acids increase response and expression of human myometrial oxytocin receptor
Alfredo M Germain1, Sumie Kato, Jorge A Carvajal
1Department of Obstetrics and Gynecology, Pontificia Universidad Católica de Chile School of Medicine, Santiago, Chile.
Objective:
We tested the hypothesis that during intrahepatic cholestasis of pregnancy bile acids activate the myometrial oxytocin receptor pathway.
Study Design:
Myometrial sensitivity to oxytocin and oxytocin-receptor messenger RNA and protein level was investigated. The ability of cholic acid to mediate such changes was evaluated.
Results:
Cholestasis patients required lesser oxytocin to elicit four uterine contractions in 10 minutes (1.3+/-0.6 vs 3.6+/-0.8 U, P<.05, n=7) and had lower in vitro ED(50) (1.6 x 10(-10) mol/L vs 1.0 x 10(-8) mol/L, P<.05, n=7) than controls. The 24-hour incubation of control myometrial strips (n=7) with cholic acid (20 micromol/L) increased oxytocin sensitivity. Incubation of cultured myometrial cells (n=5) with cholic acid increased oxytocin-receptor expression (messenger RNA and protein).
Conclusion:
We demonstrate that during intrahepatic cholestasis of pregnancy, an activation of the oxytocin receptor pathway occurs. This event seems to be the result of a cholic acid-mediated increase in oxytocin-receptor expression.
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