Altered responsiveness of small uterine arteries in women with idiopathic menorrhagia.

Abstract

This study was undertaken to study vascular reactivity of small myometrial arteries in women with idiopathic menorrhagia. Small myometrial arteries were isolated from 6 patients with idiopathic menorrhagia and 4 controls. The contractile responses to thromboxane mimetic (U46619) and endothelin-1 were assessed before and after incubation with N(w)-nitro-L arginine methyl ester alone or in combination with indomethacin (Indo). Endothelium-dependent dilation to bradykinin and basal tension were compared before and after incubation with N(w)-nitro-L arginine methyl ester alone, or with N(w)-nitro-L arginine methyl ester in combination with indomethacin. Constriction to endothelin-1 was enhanced in idiopathic menorrhagia arteries (P < .05). Idiopathic menorrhagia arteries demonstrated enhanced basal tension after incubation with N(w)-nitro-L arginine methyl ester, which was further exaggerated by indomethacin. NOS inhibition had no effect on basal tension in controls, but basal tension was enhanced after inhibition of cyclooxygenase-derived products (P < .05). Bradykinin-mediated dilation was significantly increased in idiopathic menorrhagia (P < .05). The presence of functional alterations in small myometrial arteries could contribute to idiopathic menorrhagia.