Antitachyphylactic effects of progesterone and oxytocin on term human myometrial contractile activity in vitro.

Oct 1, 1993Obstetrics and gynecology

Progesterone and oxytocin reduce rapid loss of response in full-term human uterine muscle contractions in the lab

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗

Abstract

The frequency of myometrial contractions and tonus increased with progesterone and oxytocin treatments compared to buffer.

Progesterone enhanced both the frequency of contractions and the muscle tone in human myometrial tissue.
Superfusion with oxytocin alone caused a gradual decrease in contraction frequency after 60 minutes.
Progesterone combined with oxytocin maintained contraction frequency without the observed decrease seen with oxytocin alone.
The activity area of contractions was greater with lower doses of oxytocin but decreased with higher doses and when treated with progesterone.

AI simplified

OBJECTIVE: To determine whether progesterone causes any changes in the action of oxytocin on the contractile activity of term human myometrium in vitro.

METHODS: Myometrial biopsies from 13 term pregnant women undergoing cesarean delivery were immediately immersed in Hepes buffer or buffer containing 5 micrograms/mL progesterone. In the laboratory under a stereomicroscope, the specimens were dissected into 1 x 7.5-mm muscle strips. These were mounted into six tissue baths and superfused with Hepes buffer and buffer containing 5 micrograms/mL progesterone, 5 micrograms/mL progesterone plus 10 microU/mL oxytocin, 5 micrograms/mL progesterone plus 100 microU/mL oxytocin, 10 microU/mL oxytocin, and 100 microU/mL oxytocin. Isometric tension was recorded constantly for at least 3 hours.

RESULTS: The frequency of myometrial contractions and tonus increased by superfusion with progesterone, progesterone plus oxytocin, and oxytocin alone compared to buffer. In addition, a gradual decrease in frequency was observed after 60 minutes of contractions with oxytocin alone, whereas progesterone plus oxytocin had no such decrease. The activity area of contractions was greater with 10 microU/mL oxytocin and decreased with progesterone, progesterone plus both concentrations of oxytocin, and 100 microU/mL oxytocin alone, compared to buffer.

CONCLUSIONS: Progesterone stimulated the frequency of contractions and tonus of strips from the lower uterine segment of term human myometrium. A lasting increase in the frequency of contractions was observed with superfusion of progesterone plus oxytocin, suggesting that progesterone counteracted the reaction of tachyphylaxis to oxytocin.

Antitachyphylactic effects of progesterone and oxytocin on term human myometrial contractile activity in vitro.

Abstract

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief