| Abstract: | Preimplantation rabbit embryos collected at the early morula stage were cultured to blastocysts in the presence of 3H]inositol. The blastocysts were lysed, and both the aqueous and lipid portions were analysed for incorporated radioactivity. Thin-layer chromatographic separation of the lipid portion indicated that 3H]inositol was incorporated into phosphatidylinositol, phosphatidylinositol 4-phosphate, and phosphatidylinositol 4,5-bisphosphate. HPLC anion-exchange chromatography indicated that 3H]inositol was incorporated into inositol phosphates, including the two second messengers, inositol 1,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate, and also inositol monophosphate and inositol 1,4-bisphosphate. These results provide evidence that rabbit blastocysts may have an active phosphatidylinositol second messenger system, which may be responsive to intrauterine factors or intraembryonic paracrine factors. © 1993 Wiley-Liss, Inc. |
