Bruner-Tran KL, Zhang Z, Eisenberg E, Winneker RC, Osteen KG. Down-regulation of endometrial matrix metalloproteinase-3 and -7 expression in vitro and therapeutic regression of experimental endometriosis in vivo by a novel nonsteroidal progesterone receptor agonist, tanaproget. The Journal of clinical endocrinology and metabolism. 2006 Apr;91(91). 1554-60. PMID: 16418212 [PubMed]
Endometriosis, the growth of endometrial tissue outside the uterus, is principally an estrogen-dependent disease. In contrast, exposure to progesterone during pregnancy or therapeutically has been shown to provide benefit to some women with this disease. However, recent research suggests that the presence of endometriosis impairs the capacity of the eutopic endometrium to respond to endogenous progesterone.