Effect of Inhaled Propylene Oxide on Reproductive Parameters in Fischer 344 Rats

Effect of Inhaled Propylene Oxide on Reproductive Parametersin Fischer 344 Rats. HAYES, W. C, KIRK, H. D., GUSHOW, T. S.AND YOUNG, J. T. (1988). Fundam. Appl. Toxicol 10, 82–88.Reproductive parameters in Fischer 344 rats were evaluated followinginhalation of propylene oxide (PO) for two successive generations.Thirty male and 30 female rats were exposed to 0, 30, 100, or300 ppm PO for 6 hr/day, 5 days/week for 14 weeks and then matedto produce the f, litters. After weaning, 30 randomly selectedf₁, pups/sex/group were exposed to PO for 17 weeks and subsequentlymated to produce the f₂ litters. Reproductive parameters examinedincluded fertility, litter size and neonatal growth, and survival.All adults and selected weanlings were examined for gross andhistologic lesions. Toxicity due to PO was demonstrated by decreasedbody weights of parental f_o and f₁, rats at 300 ppm. No treatment-relatedeffects on fertility (mating or conception) were observed ineither f_o or f₁ matings. Neonatal survival indices for f₁, orf₂ litters revealed no treatment-related effects. Litter sizewas decreased in the f₁, rats exposed to 100 ppm PO. However,the litter size in the 300 ppm group was comparable to the controlgroup, and no effect on litter size was shown in PO-exposedf₂ litters. Pup weights were unaffected by parental exposureto PO in either generation. Pathologic examination of adultsand weanlings revealed no changes considered due to PO. Basedon these results, it is concluded that inhalation exposure toPO at levels up to 300 ppm over two generations did not produceany adverse effects on reproductive function.