EXPRESSION OF CONNEXIN-43 IN HUMAN MYOMETRIUM AND LEIOMYOMA

OBJECTIVES: The expression of connexin-43 was examined in human leiomyomas and in autologous myometrium. STUDY DESIGN: Indirect immunofluorescence was used to detect connexin-43 gap junctions in myometrial and leiomyoma tissues and in primary cultures. Immunoblot and Northern analyses were used to examine the levels of connexin-43 protein and cx43 messenger ribonucleic acid in primary cultures. RESULTS: Connexin-43 gap junctions were detected in leiomyoma tissue from nonpregnant premenopausal women but not in autologous myometrial tissue. Connexin-43 gap junctions form spontaneously in primary cultures of myometrium and leiomyoma in the presence of 17beta-estradiol. Fluorescent dye injection confirmed that the gap junctions were coupled in the primary cells. Connexin-43 protein and messenger ribonucleic acid levels generally were higher in leiomyoma cells compared with those of autologous myometrial cells. Steady-state levels of cx43 messenger ribonucleic acid decreased with addition of medroxyprogesterone acetate to the cultures. CONCLUSIONS: Differences in the levels of cx43 expression in leiomyoma and myometrial cells may reflect differences in responses to steroid hormones.