Histochemical and ultrastructural study of lactic dehydrogenase in chemically induced lung cancer.

Light and electron microscopy studies of lactic dehydrogenase activity were carried out in embryonic, neonatal, and adult mouse lungs and in lungs undergoing chemically induced carcinogenesis. Embryonic mouse lungs were collected on the 6th, 12th, and 18th days of gestation; 1-day-old lungs were used for the neonatal model. These were compared with adult normal mouse lung and lungs of the animals treated with 4-nitroquinoline 1-oxide at a monthly interval until cancer developed. Enzymatic activity was seen in the embryonic, precancerous, and malignant lung tissues and was found diffusely in the cytoplasm of the epithelial cells.