Comparison of lung antioxidant levels in humans and laboratory animals

Basal lung concentrations of ascorbic acid (AA), nonprotein sulfhydryls (NPSH), and alpha-tocopherol (alpha-T) were determined in rabbits, guinea pigs, rats, hamsters, mice, domestic pigs and sheep, and in human lung samples obtained from cancer surgery patients. Significant differences were found among the laboratory animals: AA levels ranged from 25.6 mg% (mg/100 g wet weight) in hamsters to 41.7 mg% in mice, NPSH from 50.9 mg% in rats to 84.7 mg% in rabbits, and alpha-T from 1.01 mg% in hamsters to 2.74 mg% in rats. Porcine lung AA and NPSH concentrations approximated those of the laboratory animals and their alpha-T levels were the highest of all species studied. Sheep lung AA levels were comparable to those in the other species, although their NPSH and alpha-T levels appeared to be lower. Human lung concentrations of NPSH (5.2 mg%) and alpha-T (0.85 mg%) appeared low, whereas the mean AA concentration (22.1 mg%) was similar to that of laboratory animals. A partial correlation was found between AA and alpha-T levels and between NPSH and alpha-T levels in the 5 laboratory animal species.