Placental transfer and tissue distribution of 14C-styrene: an autoradiographic study in mice.

The distribution of 14C-styrene was studied in the pregnant mouse using a whole body low temperature autoradiographic technique. In unsectioned tissues studied by liquid scintillation the concentrations of styrene and its metabolites in maternal and fetal blood and organs and in the placenta and amniotic fluid were determined. The organs which had higher concentrations of volatile styrene were maternal lung, kidney, liver, adipose tissue, and brain in mice killed shortly after injection. Non-volatile metabolites were localised in the lung, liver, kidney, gall bladder, and intestine. There were considerable amounts of radioactivity in the fetuses, though the concentrations were not as high in the maternal tissues. Fetal tissue levels were almost the same as maternal brain in mice killed from one to six hours after injection. The concentrations of styrene and its metabolites in placenta and amniotic fluid were about twice those in the fetal tissues. The placenta seems to play the part of a barrier for the fetus.