Expression of antiangiogenic prolactin fragments in the placentas of women with pregnancy induced hypertension.

It has been reported that prolactin (PRL) is cleaved to 14 or 16 kDa fragments by cathepsin D in vitro and in vivo, and that such fragments exhibit antiangiogenic and proapoptotic properties. The aim of this study was to investigate the relationship between pregnancy induced hypertension (PIH) and the placental expression of antiangiogenic PRL fragments and cathepsin D. Placental expression of PRL fragments and cathepsin D was evaluated by Western blot analysis in a group of 9 pregnant women consisting of 5 normal pregnancies and 4 severe PIH cases. Antiangiogenic PRL fragments were detected in 4 placental samples from all PIH cases but not detected in those from normal pregnancies (p<0.05). The expression of cathepsin D in PIH placentas was significantly lower than that in those without PIH (p<0.05), while the placental expression of procathepsin D was significantly greater in PIH cases than in the normal pregnancies (p<0.05). These data suggest that antiangiogenic PRL fragments in the placenta may be present only in PIH cases, and that PRL fragments in the placenta might be implicated in the pathophysiology of PIH.