PLACENTAL PROTEIN 12 (PP12) IN MENSTRUAL FLUID

Previously placental protein 12 (PP12) were found in the human endometrium. PP12-like immunoreactive material is released into menstrual fluid where it occurs at concentrations from 43-32,000 .mu.g/l. The PP12 levels in menstrual fluid are 2- to 2000 fold higher than in serum of the same individuals suggesting that the protein either concentrates or is produced in the endometrium. The addition of protease inhibitors has no effect on the PP12 levels. In radioimmunoassay, the dose-response curves of menstrual fluid PP12 and placental PP12 are parallel. Experiments with fused rocket immunoelectrophoresis show that menstrual and placental PP12 are indistinguishable from each other. In gel filtration, menstrual PP12 has the same MW as that of purified placental PP12. By immunoperoxidase staining, PP12 is localized in the glandular epithelial cells of the menstrual endometrium. The glandular localization and high concentration of PP12 in menstrual fluid, as compared with PP12 levels in serum and endometrium, suggest that PP12 may be secreted by the endometrium.