Effects of corticotrophin releasing hormone on contractile activity of myometrium from pregnant women.

OBJECTIVE

To determine whether corticotrophin releasing hormone plays a role in the regulation of tone in term nonlabouring human myometrium.

SETTING

A teaching hospital research laboratory.

SAMPLE: Thirty-seven women undergoing elective nonlabour caesarean section under regional anaesthesia.

METHODS

Human corticotrophin releasing hormone (1, 10, 100 nmol/L) was added to strips of term, nonlabouring myometrium mounted in an organ bath, and the effect on spontaneous, oxytocin (1 nmol/L) or prostaglandin F2alpha (100 nmol/L) stimulated contractions determined. Cyclic adenosine monophosphate (cAMP) content of the tissue was also determined by enzyme immunoassay.

RESULTS

Corticotrophin releasing hormone did not affect myometrial tension development in any of the experimental protocols. cAMP increased transiently after addition of corticotrophin releasing hormone (166.7 +/- 12.7% at 1 minute) but this was not reflected by any change in tension.

CONCLUSIONS

This study suggests that despite high maternal plasma concentrations of corticotrophin releasing hormone in pregnancy at term, this peptide is unlikely to play a direct role in the control of myometrial contractility in nonlabouring myometrium.