Expression of uterine and cervical epithelial cadherin during relaxin-induced growth in pigs.

Epithelial cadherin (E-cadherin), a member of the cadherin family of calcium-dependent adhesion molecules, is present in reproductive tissues. Relaxin, a hormone important for uterine and cervical growth in pigs, increases the expression of E-cadherin in the MCF-7 mammary epithelial cell line. The objective of this study was to characterize the expression of E-cadherin during relaxin-induced growth of the uterus and cervix in an immature pig model, independent of high circulating steroids. After administration of relaxin to prepubertal gilts, the uterus and cervix were collected. E-cadherin mRNA and protein were measured by northern and western blot analysis, respectively. A 120 kDa protein band, corresponding to E-cadherin, was detected in all tissues examined. Relaxin significantly (P < 0.05) increased the amount of E-cadherin protein in the uterus (P < 0.05), whereas no significant changes were observed in E-cadherin protein in the cervix. A 4.2 kb E-cadherin transcript was detected in all tissues and E-cadherin mRNA was significantly higher (P < 0.05) in uteri from relaxin-treated gilts compared with control gilts. E-cadherin was localized by immunocytochemistry to the epithelial cells of the uterine and cervical lumen, and the uterine glandular epithelium. Quantitative analysis revealed that administration of relaxin significantly increased (P < 0.05) the height of the uterine luminal epithelium compared with that of the controls. This is the first report of the expression of E-cadherin in the uterus and cervix of pigs. The findings from this study indicate that relaxin increases the expression of uterine E-cadherin in the reproductive tract of pigs. Administration of relaxin to prepubertal gilts in vivo increased uterine epithelial cell growth independent of circulating steroids, with a concomitant increase in E-cadherin expression.