Biochemical effect of ozone exposure in rats exposed to cigarette smoke

Rats were exposed to three cigarettes per day for 35 days, under realistic conditions. Pulmonary glucose-6-phosphate dehydrogenase (G-6-PD) activity in the exposed animals increased 27% over control values (P less than .05). Subsequent exposure to acute, high-dose ozone (3 ppm for 4 hr) decreased the augmented G-6-PD activities to near normal levels, whereas ozone exposures in animals not exposed to cigarette smoke caused mild decreases in pulmonary G-6-PD activities. The importance of these findings with respect to the susceptibility of the smoker to oxidant exposures is unknown.