The effect of a single intraperitoneal dose of the hepatocarcinogen 4-dimethylaminoazobenzene on the rough-surfaced endoplasmic reticulum of the liver of the rat.
1. Changes in the structure and function of the rough-surfaced endoplasmic reticulum of the rat liver as deduced by electron microscopy, polysome analysis and the amino acid-incorporating activity of microsome fractions have been followed at various time-intervals after a single intraperitoneal dose of the hepatocarcinogen 4-dimethylaminoazobenzene. 2. The earliest effect observed was detachment of polysomes and disorganization and vesiculation of the cisternae of the rough-surfaced endoplasmic reticulum. This occurred after 6hr. 3. Subsequent to this was a phase of polysome disaggregation accompanied by impaired amino acid-incorporating activity by microsomes together with a much enhanced stimulating effect of polyuridylic acid on amino acid uptake. This reached a maximum at 24hr. 4. By 40hr. polysomes had re-formed and the amino acid-incorporating activity, together with the polyuridylic acid effect, were similar to those in controls. 5. It was not until 112hr. that something like the normal structure of the rough-surfaced endoplasmic reticulum was re-established. 6. It is not yet possible to relate these changes specifically with the process of azo-dye carcinogenesis.
D000818:Animals; D002247:Carbon Isotopes; D002273:Carcinogens / Q000494:pharmacology*; D004721:Endoplasmic Reticulum / Q000187:drug effects*; D008099:Liver / Q000166:cytology* / Q000187:drug effects*; D008297:Male; D008854:Microscopy, Electron; D008861:Microsomes / Q000378:metabolism; D009374:Neoplasms, Experimental / Q000139:chemically induced; D010649:Phenylalanine / Q000378:metabolism; D011119:Polynucleotides / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012270:Ribosomes / Q000378:metabolism; D014500:Uracil Nucleotides / Q000494:pharmacology; D004124:p-Dimethylaminoazobenzene / Q000494:pharmacology*
D002247:Carbon Isotopes; D002273:Carcinogens; D011119:Polynucleotides; D012333:RNA, Messenger; D014500:Uracil Nucleotides; D010649:Phenylalanine; D004124:p-Dimethylaminoazobenzene