Unscheduled DNA synthesis correlated to alkylation of hemoglobin in individuals occupationally exposed to propylene oxide.

Exposure to propylene oxide was determined previously by the degree of alkylation of hemoglobin measured on the histidine residue as N-3-(2-hydroxypropyl) histidine, using blood samples from 8 propylene oxide-exposed employees and 13 unexposed referents. Mononuclear leukocytes isolated from the same blood samples were used to quantify DNA repair proficiency following an in vitro challenge with the carcinogen, N-acetoxy-2-acetylamino-fluorene. Decreases in the DNA repair proficiency index correlated significantly to in vivo exposure levels to propylene oxide (r = -0.64, p less than 0.03). These data suggest a possible short-term biological assay for monitoring the in vivo genotoxic effects of propylene oxide exposure in the human population.