Oxidative phenotype polymorphism (P450 2D6) and metabolism of toluene

Oxidative phenotype P-450 2D6 was examined using sparteine test in 3 groups of persons to determine if there is a coincidence in the defect of the oxidative biotransformation of sparteine and impaired oxidation of toluene, which could explain interindividual differences in the amounts of hippuric acid in the urine in exposed persons. The following groups of persons were examined: 30 rotogravure printers exposed to toluene vapors at concentrations of 8-307 ppm; 20 workers, 2 months after the cessation of the long-term exposure to toluene at concentrations of 104-1,170 ppm; 48 healthy volunteers with no exposure to toluene. Among the 98 persons 5 poor metabolizers (PMs) of sparteine were found, none in the group of printers exposed to toluene. In the experimental exposure chamber 5 PMs and 6 extensive metabolizers (EMs) were exposed to toluene concentration of 245 ppm for 5 hours. Hippuric acid and o-cresol in the urine, and toluene both in blood and in alveolar air were measured. However, no significant differences were found in either of these parameters between the PM and EM groups. Thus, the sparteine test does not appear to be applicable in the identification of persons with higher risk arising from toluene exposure.