Direct effects of nicotine on rabbit preimplantation embryos.

The effects of various concentrations of nicotine on the in vitro development of 1-cell rabbit preimplantation embryos and on the DNA-synthesis of 4-day-old rabbit blastocysts are investigated. Exposure of rabbit preimplantation embryos to concentrations of nicotine higher than 1 X 10(-3) M results in a marked decrease in the in vitro development and in DNA-synthesis. Concentrations of nicotine below 1 X 10(-3) M have no effect on these early embryos. It can be concluded that the concentrations of nicotine which exert a direct embryotoxic effect are higher than the concentrations that may be expected in the blood circulation of humans considered to be "normal smokers".