Induction of endometrial plasminogen activator–inhibitor 1: a possible mechanism contributing to the effect of intrauterine levonorgestrel in the treatment of menorrhagia  Eeva-Marja Rutanen, M.D., Ph.D., Ritva Hurskainen, M.D., Patrik Finne, M.D., Kristiina Nokelainen  Fertility and Sterility  Volume 73, Issue 5, Pages 1020-1024 (May 2000) DOI: 10.1016/S0015-0282(00)00489-1

Figure 1 Representative Northern blot analysis of tissue-type plasminogen activator (t-PA) mRNA and plasminogen activator inhibitor 1 (PAI-1) mRNA in the human endometrium. Total RNA was extracted from endometrial tissue samples obtained from women with and without objective menorrhagia. Samples were collected before any treatment and 6 months after insertion of a levonorgestrel-releasing intrauterine system (LNG–IUS). The phase of the menstrual cycle is indicated above each lane. P, proliferative; S, secretory; M, menstrual; L, LNG–IUS endometrium. The P and S lanes before L lanes come from the same women before the LNG–IUS was inserted. A human 28S rRNA probe was used to normalize the amount of RNA loaded in each lane. Rutanen. Intrauterine levonorgestrel system. Fertil Steril 2000. Fertility and Sterility 2000 73, 1020-1024DOI: (10.1016/S0015-0282(00)00489-1)