DISTRIBUTION OF ANNEXIN-I AND ANNEXIN-II IN TERM HUMAN FETAL MEMBRANES, DECIDUA AND PLACENTA

Annexin I and II are calcium binding proteins implicated in the regula tion of a number of cellular functions, including secretory processes, prolactin release and prostaglandin formation. The cellular distribut ion of these proteins was examined in human term placenta, fetal membr anes (amnion and chorion laeve) and decidua using immunohistochemisty Annexin I was found in amnion epithelial cells and chorion laeve troph oblast but not in decidua, and was located in the syncytiotrophoblast cells of placenta. Annexin II and annexin II light-chain were located in the amnion epithelial cells, the cells of the mesenchymal layer bet ween the amnion and chorion laeve, chorion laeve trophoblast and endot helial cells lining the blood vessels in the decidua. In contrast to a nnexin I, annexin II was located in the villous core and not the syncy tiotrophoblast cells in the placenta. There was no apparent change in the distribution of these annexins during labour. These findings indic ate that the cellular distribution of these annexins is different, and may be an important consideration when examining their synthesis or a ction in tissues and in vitro with mixed cell populations and tissue h omogenates. (C) 1996 W. B. Saunders Company Ltd