[Changes in the matrix properties of chromatin during aminoazocarcinogenesis]

Male rats were on a diet containing 3-methyl-4-dimethylaminoazobenzol, a carcinogen. There were found no changes either in the electrophoretic total spectrum of deoxyribonucleoprotein (DNP) or in nonhistone proteins; the character of DNA and DNP melting curves or the matrix capacity of DNA extracted from the rat liver also remained unchanged. DNP of the tumour tissue acted more actively in the capacity of the matrix for the RNA synthesis in vitro in the system with the animal or bacterial RNA-polymerase with low substrate concentrations (2-10-5 M); but with high concentrations of each one of the substrates (2-10-3 M) RNA synthesis was the same as in control. With nuclear lysis in the solution with alkaline pH the percentage of RNA-polymerase activity, which it was possible to extract from the complex with chromatin, decreased considerably in rats given carcinogen.