The following abstract presents results of a study conducted by a contract laboratory for the National Toxicology Program. The findings were not evaluated in accordance with the levels of evidence for reproductive or developmental criteria established by NTP in March 2009. The findings and conclusions for this study should not be construed to represent the views of NTP or the U.S. Government.
A Task la study in CD-1 mice on ddC at dose levels of 200, 400, and 1000 mg/kg/day was conducted. The only toxicity observed in the males was a mild macrocytic hyperchromic anemia at the 1000 mg/kg/day dose. Similarly, maternal toxicity in the form of macrocytic hyperchromic anemia was observed at 1000 mg/kg/day in the female group. Reproductive and developmental toxicity was produced by the 400 and 1000 mg/kg/day dosages. Observations at the 1000 mg/kg/day dose included increased resorption rates, embryolethality, decreased fetal and pups weights, and gross external malformations. Observations at 400 mg/kg/day were limited to decreased fetal and pup weights. In males, the no observable adverse effect level for toxicity was 400 mg/kg/day. The 400 mg/kg/day dosage of ddC was the approximate NOAEL for maternal toxicity, and 200 mg/kg/day is the NOAEL for developmental toxicity.