PRESENCE OF DIOXINS IN HUMAN FOLLICULAR-FLUID - THEIR POSSIBLE STAGE-SPECIFIC ACTION ON THE DEVELOPMENT OF PREIMPLANTATION MOUSE EMBRYOS

Examination of human follicular fluid revealed the presence of polychl orinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs) at concentra tions of approximately 1 pg/ml (0.01 pg TEQ/ml). To study their possib le action, two-cell mouse embryos were cultured in the presence of 2,3 ,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at concentrations between 0.5 and 100 pM and evaluated at 24-h intervals for their development to th e eight-cell and blastocyst stages. The percentage of eight-cell embry os exposed to TCDD at 1, 2, and 5 pM concentrations was significantly lower than that of controls. However, blastocyst formation of the surv iving eight-cell embryos was accelerated, with the number of cells in the blastocysts increased in a dose-dependent manner. Findings suggest that PCDDs and PCDFs may be present in human reproductive fluid and m ay exert some stage-specific effects on early embryonic development. ( C) 1998 Academic Press.