Erythromycin inhibits prostaglandin F2alpha-induced contractions of myometrium isolated from non-pregnant rats.

OBJECTIVE

The aim of this study was to investigate the effects of erythromycin on prostaglandin F2alpha (PGF2alpha)-induced contractions of isolated myometrial strips from non-pregnant rats.

DESIGN

In vitro pharmacological study.

SETTING

Firat University Faculty of Medicine.

SAMPLE: Myometrium samples were taken from 55 adult Wistar rats.

METHODS

Myometrial strips were isolated from mature, non-pregnant Wistar rats. Isometric contractions of these strips were induced with 1 microM PGF2alpha. Effects of 0.01, 0.1, 0.2, 0.5 and 1 mM erythromycin on the frequency and amplitude of these PGF2alpha-induced contractions were recorded.

MAIN OUTCOME MEASURES: The inhibition of prostaglandin F2alpha-induced contractions in vitro.

RESULTS

Application of 0.01 mM erythromycin had no effect on either amplitude or frequency of contractions. However, 0.1, 0.2, 0.5 and 1 mM erythromycin decreased the frequency and amplitude of PGF2alpha-induced contractions. The inhibitory effect of erythromycin on amplitude was 27%, 38%, 54% and 83% (P < 0.05), and that on frequency was 10%, 16%, 32% and 61% (P < 0.05) at 0.1, 0.2, 0.5 and 1 mM concentrations, respectively.

CONCLUSION

The results of this study demonstrate that erythromycin inhibits PGF2alpha-induced contractions in rat myometrium. Because PGF2alpha-induced contractions have been suggested to be involved in the pathogenesis of primary dysmenorrhoea, effects of erythromycin in this clinical entity may present a new approach for the treatment.