Related Experiment Video
Updated: Jun 28, 2026

Contractility Measurements of Human Uterine Smooth Muscle to Aid Drug Development
Published on: January 26, 2018
Progesterone, but not 17-alpha-hydroxyprogesterone caproate, inhibits human myometrial contractions
Nicole K Ruddock1, Shao-Qing Shi, Sangeeta Jain
1Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX, USA.
Objective:
The aim was to determine whether progesterone (P4) or 17-alpha-hydroxyprogesterone caproate (17P) directly inhibit human uterine contractility in vitro and thereby clarify their mechanisms of action.
Study Design:
Myometrial tissues were suspended in organ chambers and exposed for 2 to 20 hours to varying concentrations of P4 or 17P or solvent. Contractile activity was registered, stored, and analyzed. Dose response curves were then generated for P4 or 17P at various times.
Results:
P4 significantly inhibited spontaneous contractility dose dependently. The inhibition was not blocked by RU486 but was reversible after washing. Surprisingly, 17P dose dependently stimulated contractility. HPLC and GC-MS methods were used to determine the detectable concentrations of progestins in the baths.
Conclusion:
P4, at concentrations equivalent to those present in the placenta and uterus, inhibit spontaneous myometrial contractility in vitro by nongenomic mechanisms.
Related Concept Videos
Drugs for Peptic Ulcer Disease: Prostaglandin Analogs as Mucosal Protective Agents
Non-steroidal anti-inflammatory drugs (NSAIDs) can induce peptic ulcers by inhibiting cyclooxygenase, decreasing...
Hormonal Regulation of the Menstrual Cycle
At puberty, GnRH begins a pulsatile release pattern, which triggers the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The frequency and amplitude of GnRH pulses vary across the menstrual cycle, with faster pulses favoring LH release and slower pulses favoring FSH release.
Nondepolarizing (Competitive) Neuromuscular Blockers: Pharmacological Actions
Although all competitive neuromuscular blockers are designed...
Gonadal and Placental Hormones
In males, testosterone is the primary gonadal androgen. It plays a central role in the maturation of male reproductive organs — the penis and testes. Additionally, testosterone is instrumental in the development of secondary sexual characteristics — a deep voice as well as facial and pubic hair growth — and...
Ovarian Cycle
Nondepolarizing (Competitive) Neuromuscular Blockers: Mechanism of Action
Competitive antagonists prevent acetylcholine from binding to its receptor, inhibiting membrane depolarization. Without conformational changes or intrinsic...

