OBJECTIVE: Ghrelin is a peptide that regulates maternal appetite and energy expenditure as well as playing a role in fetal nutrition. The purpose of the study was to investigate the effects of ghrelin on human myometrial contractility in vitro.STUDY DESIGN: Biopsy specimens of human myometrium were obtained at elective cesarean section (n=21). Dissected myometrial strips suspended under isometric conditions, undergoing spontaneous and oxytocin-induced contractions, were exposed to cumulative additions of ghrelin in the concentration range of 1 nmol/L to 1 mu mol/L. Control experiments were performed simultaneously.RESULT: Ghrelin exerted an inhibitory effect on contractility, compared with control strips. The mean maximal inhibition values were as follows: 33.66% +/- 2.63% for spontaneous contractions (n=6; P<.05), and 31.55% +/- 4.64% for oxytocin-induced contractions (n=6; P<.05).CONCLUSION: This inhibitory effect of ghrelin on uterine contractions suggests it plays a physiologic role in regulation of myometrial activity and further studies to evaluate the signaling pathways involved may help to define this role. These findings highlight the emerging role of metabolic modulation of myometrium, and particularly at extremes of body mass index measurements.