Human endometrial tissue, sampled at different periods of the reproductive cycle, expressed interstitial collagenase mRNA, protein and activity only just before and during the menstrual period. This clear-cut correlation and the inhibition of collagenase expression by progesterone and oestradiol in tissue culture point to a pivotal role of this proteinase in the mechanism of menstrual tissue breakdown and bleeding.
Marbaix, E., Kokorine, I., Henriet, P., Donnez, J., Courtoy, P., & Eeckhout, Y. (1995). The expression of interstitial collagenase in human endometrium is controlled by progesterone and by oestradiol and is related to menstruation. The Biochemical journal, 305 ( Pt 3), 1027-1030. https://hdl.handle.net/2078.5/132760 (Original work published 1995)