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The reversibility of inhibition of RNA and DNA synthesis induced by aflatoxin in rat liver. A tentative explanation for carcinogenic mechanism
Author(s) -
Lafarge C.,
Frayssinet C.
Publication year - 1970
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910060112
Subject(s) - aflatoxin , rna , carcinogen , nucleic acid , dna , carcinogenesis , transcription (linguistics) , dna synthesis , mechanism of action , in vitro , biochemistry , nucleolus , biology , chemistry , nuclear dna , microbiology and biotechnology , gene , mitochondrial dna , linguistics , philosophy , cytoplasm
Aflatoxin is a potent hepatocarcinogen. Biochemically the short‐term action which seems to be the most important is an inhibition of nucleic acid synthesis. Injection of low doses (from 500 to 1,000 μg/kg) made it possible to modulate the different inhibitions induced by aflatoxin. The following events are successively observed: first, inhibition of nucleolar RNA synthesis, then inhibition of replication and, finally, inhibition of total nuclear transcription. With such aflatoxin doses these phenomena are reversible, and the different syntheses recommence in the following order: after 24 h the total nuclear RNA synthesis; next, nucleolar RNA synthesis and lastly, after 48 h, DNA synthesis. Therefore there is a period of at least 24 h during which RNA is synthesized and DNA is not. These results may be compared to those obtained by other authors working in vitro and showing aflatoxin‐DNA binding. They support a hypothesis concerning the carcinogenesis mechanism proceeding by deletion at the genetic level.