[Ribosomal apparatus of liver cells in the process of carinogenesis induced by 4-dimethylaminoazobenzene].

A content of membrane-bound and free ribosomes, sedimentation distribution of total polyribosomes in a linear sucrose density gradient and their functional activity in a cell-free system of protein synthesis were estimated in liver of animals feeded with protein-poor rice diet containing a cancerogen, 4-dimethylaminoazobenzene (DAB) at a dose of 15 mg per day. Periods of the experiments were 1-10 days, 1-2, 3-4 and 5 months from the beginning of DAB treatment. The decrease of protein-synthesizing activity, the decrease in the content of membrane-bound ribosomes and the oncrease in the content of free ribosomes in animal liver were observed at first days of DAB action. Changes in the quantitative ratio between membrane-bound and free ribosomes (in the direction of decreasing the content of membrane-bound ribosomes) was observed at all the stages of DAB-cancerogenesis. It is supposed that the uncoupling of ribosome-membrane bonds in endoplasmic reticulum takes an important part in cancerogenesis, disturbing intracellular regulation of protein synthesis.