DEVELOPMENTAL-CHANGES IN NEUTRAL GLYCOSPHINGOLIPIDS OF MOUSE PLACENTA

The mammalian placenta is a unique organ for the study of developmenta l changes. Placentas of laboratory animals such as the mouse allow for the determination of the exact stage of pregnancy, which cannot be ac hieved with human placenta. In this study, neutral glycosphingolipids were isolated from mouse (inbred strain C57BL/6) placentas, from day 1 0 to day 18 of gestation, and were separated by high performance thin layer chromatography. Densitometric measurements after orcinol stainin g showed, at day 10 of gestation, the presence of mono-, tetra-, tri- and dihexosylceramide in decreasing quantities, as well as four uniden tified spots. On day 12, the glycosphingolipid composition changed wit h the disappearance of the unidentified spots and the appearance of an orcinol positive spot migrating similarly to the Forssman antigen; no further changes occurred between days 12 and 18 of gestation. The ide ntity of the Forssman-like glycosphingolipid with the Forssman antigen was established by binding of I-125 labelled Helix pomatia agglutinin (alpha-GalNAc specific) to.glycosphingolipids separated on high perfo rmance thin layer chromatography plates, and by the reaction of the is olated glycosphingolipid with a monoclonal anti-Forssman antibody. The appearance of the Forssman antigen at day 12 of gestation coincided w ith the day of final maturation of the mouse placenta and subsequent c essation of growth, suggesting a possible role of the glycosphingolipi d during embryonic development.