Increased expression of prolactin receptor mRNA in adenomyotic uterus in mice

To investigate changes in uterine prolactin receptor (PRLR) expression in advanced uterine adenomyosis induced by ectopic pituitary isograft, the amount of PRLR mRNA was measured, by a quantitative competitive PCR, in both normal uteri and uteri with adenomyosis in mice at 20 days or 4, 5 and 6 months after pituitary grafting. There was no difference in the amount of PRLR mRNA between the normal uteri and uteri with pituitary grafts, at 20 days after grafting. At 4-6 months after the operation, however, uteri with adenomyosis contained 2-10 times more PRLR mRNA than did in intact uteri, and the increased amount accompanied the advance of the pathological disorder. The ratio of the short to the long form of PRLR mRNA was little affected by the progress of adenomyosis. These findings suggest that increases in the amount of functional PRLR are in fact a result of the progress of adenomyotic changes, rather than simply a result of elevated circulating prolactin levels.