Pharmacokinetics of Methanol and Formate in Female Cynomolgus Monkeys Exposed to Methanol Vapors

Dr. Medinsky and colleagues of the Chemical Industry Institute of Toxicology sought to determine how formate, a metabolite produced when methanol is broken down by the body, is formed and removed in monkeys after they have been exposed to methanol vapors. The investigators exposed female cynomolgus monkeys to environmentally relevant concentrations (10, 45, or 200 parts per million) of methanol vapors and to one high dose (900 ppm) for two hours. They also exposed monkeys that had been fed a diet deficient in folic acid to the highest methanol concentration to determine whether monkeys that are deficient in folic acid accumulate more formate than normal animals. In order to increase the sensitivity of their measurements, and to differentiate between the formate that naturally occurs in the body (endogenous formate) and that which results from methanol exposure, the investigators used methanol tagged with radiolabeled carbon.