Teratogenicity of n-propanol and isopropanol administered at high inhalation concentrations to rats

As part of a teratological evaluation of several alcohols, 10,000, 7000 and 3500 ppm n-propanol or isopropanol were administered by inhalation to groups of 15 pregnant Sprague-Dawley rats for 7 hr/day on gestation days 1-19. The dams were killed on day 20. Half of the foetuses were examined for skeletal defects and the others for visceral defects using the Wilson technique. The highest concentration of n-propanol produced only minimal maternal toxicity, as indicated by observation and by measurement of weight gain and feed and water intake. In contrast, the same concentration of isopropanol produced narcosis in the dams, retarded body-weight gain and reduced the feed intake. At 7000 ppm isopropanol, body-weight gain was retarded but there were no other observable effects in the dams. Following exposure to 10,000 ppm of either alcohol, there were significant (P less than or equal to 0.05) increases in resorptions and decreases in foetal weights compared with the control groups. Foetal weights were also reduced significantly following exposure to 7000 ppm of either alcohol and to 3500 ppm isopropanol. Significantly more litters had malformations following exposure to 10,000 or 7000 ppm of either alcohol, but these effects were seen only in the presence of maternal toxicity. At 3500 ppm, no detectable teratogenic effects were produced by either solvent.