The inhibition of urease and succinoxidase by metabolic products of p-dimethylaminoazobenzene and by some related amines

A Histochemical Study of the Early Stages of Carcinogenesis in Rat Liver: Localization of Fluorescent Carcinogen and Changes in Succinic Dehydrogenase Activity

“…According to the first, the protein-deletion hypothesis (Miller and Miller, 1955) the dye becomes bound to a soluble cytoplasmic protein which is then " lost ", in that it is not found in the tumour cells. The second (Elson and Hoch-Ligetti, 1945;Elson, 1958) holds that the more important phenomenon is the damage to the Krebs cycle produced by metabolites that inhibit succinic dehydrogenase.It seemed of interest to test the localization and effect on succinic dehydrogenase of a structurally similar compound, 4-dimethylaminostilbene, which also produces cholangiomata when injected into rats (Elson, 1952 (Diet C;Elson, 1952). Some rats, designated "normal animals" were fed on a wellbalanced diet (M.R.C.…”

“…According to the first, the protein-deletion hypothesis (Miller and Miller, 1955) the dye becomes bound to a soluble cytoplasmic protein which is then " lost ", in that it is not found in the tumour cells. The second (Elson and Hoch-Ligetti, 1945;Elson, 1958) holds that the more important phenomenon is the damage to the Krebs cycle produced by metabolites that inhibit succinic dehydrogenase.…”

“…It seemed of interest to test the localization and effect on succinic dehydrogenase of a structurally similar compound, 4-dimethylaminostilbene, which also produces cholangiomata when injected into rats (Elson, 1952 (Diet C;Elson, 1952). Some rats, designated "normal animals" were fed on a wellbalanced diet (M.R.C.…”

“…It seemed of interest to test the localization and effect on succinic dehydrogenase of a structurally similar compound, 4-dimethylaminostilbene, which also produces cholangiomata when injected into rats (Elson, 1952). The advantage of this carcinogen is that it is naturally intensely fluorescent, so that if the whole molecule became bound to a cytoplasmic protein, as in the first theory, it might be seen even in very low concentration by direct fluorescence microscopy.…”

“…Animals and diet Albino Wistar male rats about 150 g. in weight were injected with 4-dimethylaminostilbene. They, and control animals, were fed on a specially prepared diet containing 5 per cent protein and an additional 0.4 per cent methionine (Diet C; Elson, 1952). Some rats, designated "normal animals" were fed on a wellbalanced diet (M.R.C.…”