Lactate dehydrogenase activity in mouse lung following 1,1-dichloroethylene: index of airway injury

Lactate dehydrogenase (LD) activity and its isozyme profile in mouse lung homogenate was affected by oral administration of 1,1-dichloroethylene (1,1-DCE). Following 100 mg 1,1-DCE/kg, LD-3 increased significantly. After 200 mg 1,1-DCE/kg, LD-5 increased whereas LD-1 and LD-2 decreased, with a resultant higher M:H ratio than controls. In contrast, elevated LD activity in serum following 1,1-DCE was predominantly associated with striking increases in total activity and changes in isozyme patterns resulting in a decrease in the M:H ratio. LD activity in liver and erythrocytes were unaffected by 1,1,-DCE administration. Although total activity in kidney was decreased, no changes were detected in the isozyme profile. Pulmonary damage induced by 1,1-DCE was reflected in significant increases in total activity and all isozymes in bronchopulmonary lavage fluids. Thus, detection of lung-derived LD activity in lung lavage fluids can be a useful index of pulmonary airway injury.