Taken together, increases in endogenous NO may downregulate MMP-2 and MMP-9 during normal pregnancy, because increases in activity of these galatinases were found under reduced NO bioavailability caused by L-NAME in the present study, implying that there may be an important mechanism enrolled in hypertensive disorders of pregnancy, since reductions in NO levels as well as increases in MMP-2 and MMP-9 have been found in pregnant women complicated by gestational hypertension and preeclampsia [12,13,14,15,20,26,27,28,87]. This evidence concerns the gene MMP9 and preeclampsia.