PURPOSE: Preimplantation embryos synthesize platelet-activating factor (PAF) and this embryo-derived PAF is required for development. PAF's signal transduction is receptor-mediated and PAF-receptor mRNA is present in early embryos. The study objective was to determine the relationship between PAF production and PAF-receptor mRNA expression levels in mouse preimplantation embryos. METHODS: Embryo-derived PAF levels were determined by radioimmunoassay. Embryonic PAF-receptor mRNA levels were determined by semiquantitated reverse transcription-polymerase chain reaction. RESULTS: Embryonic-PAF increased as time progressed at a relatively constant rate (1.4-1.9 x) except between the eight- and morula-cell stages where levels increased sevenfold. Embryonic PAF-receptor expression was highest at the two-cell stage and decreased steadily until the morula stage before increasing again. Regression analysis of embryo-derived PAF on PAF-receptor expression does not demonstrate a significant relationship. CONCLUSIONS: PAF-receptor expression (mRNA) levels decrease, while embryo-derived PAF levels decrease, as the preimplantation embryo develops. Embryonic-PAF and PAF-receptor mRNA expression do not appear related. Therefore, embryonic-PAF does not appear to regulate expression of its own receptor in vitro. The data provide a clue to the complicated cell signaling system involving PAF production and receptor expression that may help our understanding of developmental events.
PURPOSE: Preimplantation embryos synthesize platelet-activating factor (PAF) and this embryo-derived PAF is required for development. PAF's signal transduction is receptor-mediated and PAF-receptor mRNA is present in early embryos. The study objective was to determine the relationship between PAF production and PAF-receptor mRNA expression levels in mouse preimplantation embryos. METHODS: Embryo-derived PAF levels were determined by radioimmunoassay. Embryonic PAF-receptor mRNA levels were determined by semiquantitated reverse transcription-polymerase chain reaction. RESULTS: Embryonic-PAF increased as time progressed at a relatively constant rate (1.4-1.9 x) except between the eight- and morula-cell stages where levels increased sevenfold. Embryonic PAF-receptor expression was highest at the two-cell stage and decreased steadily until the morula stage before increasing again. Regression analysis of embryo-derived PAF on PAF-receptor expression does not demonstrate a significant relationship. CONCLUSIONS:PAF-receptor expression (mRNA) levels decrease, while embryo-derived PAF levels decrease, as the preimplantation embryo develops. Embryonic-PAF and PAF-receptor mRNA expression do not appear related. Therefore, embryonic-PAF does not appear to regulate expression of its own receptor in vitro. The data provide a clue to the complicated cell signaling system involving PAF production and receptor expression that may help our understanding of developmental events.
Authors: William E Roudebush; Joe B Massey; Hilton I Kort; Carlene W Elsner; Andrew A Toledo; Dorothy Mitchell-Leef; Daniel B Shapiro Journal: J Assist Reprod Genet Date: 2004-08 Impact factor: 3.412