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The direct effect of monosodium glutamate(MSG) on development in vitro of mouse embryo was examined. ICR female mice were superovulated with intraperitoneal injections of 7.5 IU PMS and 5 IU hCG 48-52h apart and mated with IGR male mice. Two-cell embryos were recovered from the oviducts at 48h post-hCG (hph) injection. Embryos were cultured in M16 containing 4㎎ BSA/㎖ upto 137hph. Four concentrations of 0. 30, 60 and 90mM MSG were tested by analysing early embryonic development such as compaction, blastocyst formation, hatching and cell number. The rates of morula stage and beyond were 95.9, 65.3, 60.3 and 2.5.3% in 0, 30, 60 and 90 mM MSG groups at 89hph, respectively. Blastocyst formation was influenced by MSG in all treated groups at 113hph. However. there was less difference between 30 and 60 mM(52:5 & 57.1%). The hatching rates of the blastocysts in the groups were 76.7. 30.6, 30.9 and 5.9% in 0, 30, 60 and 90mM MSG at 137hph, respectively. The cell numbers sharply decreased in expanded or hatched blastocysts depending on the MSG concentrations although the differences were small in the stage of early blastocyst. The results suggest that direct exposure of MSG to early mouse embryo may delay cell division, compaction and blastocyst formation in vitro.
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