Abstract
Concentrations of pyrene and total metabolites were determined for individual fetuses and selected maternal organs and tissues immediately and 6 h followinga 95βmin headβonly exposure of pregnant Wistar rats, on gestation day 17, to five levels of pyrene over therange 200β800 mg m^3^ as a microcondensation aerosol. The influence of uterine horn, side and position, on distribution to the fetus was assessed. The concentration of both pyrene and its metabolites increased more over the exposure range (eightfold) than did those in the fetus. Concentrations of pyrene or its metabolites in fetal tissues were not found to be related to its position on the uterine horn. There was an unexplained and significant (P < 0.01) higher concentration of pyrene in fetuses on the right side relative to the left side of the uterine horn for the animals killed immediately following exposure.
A comparison of the levels in maternal tissues measured immediately following the exposure and 6 h later showed that there was some redistribution of pyrene and its metabolites to the fat tissues, i.e. levels in the fat increased over the 6 h period following the exposure. Levels in the other tissues diminished dmmg this period. In general, concentrations of pyrene and its metabolites were lowest in the fetal tissues relative to those in the sampled maternal organs and tissues.