A perinatal study of toluene in CD-1 mice.

Toluene administered by inhalation at 400 ppm to CD-1 mice from Days 6 to 16 of gestation was teratogenic but not fetotoxic resulting in a significant shift in the fetal rib profile. At the lower concentration of 200 ppm, there was an increase in dilated renal pelves which might reflect desynchronization of maturation with respect to development and growth. No other effects were noted at the 200-ppm concentration. At 400 ppm, toluene also produced an increased body weight in the neonates on Day 1 postpartum following in utero exposure. Activity of lactic dehydrogenase (LDH) was significantly increased in the brains of dams exposed to 400 ppm during gestation while nonpregnant adult mice studied concurrently had significant increased activities of LDH in the liver and kidneys of the 400-ppm group. The only change in the isozyme profiles was in the kidneys of the nonpregnant adult mice in which a slight decrease in LDH-2 was observed. No other changes were noted in the dams or pups.