The metabolism of isolated rat-liver nuclei during chemical carcinogenesis. 2. 2-Acetamidofluorene, α-naphthyl isothiocyanate and 2′, 4′-dimethyl-4-dimethylaminoazobenzene

Abstract

Nuclei were isolated in 0.25.M- sucrose from livers of normal rats and rats given 2-acetamidofluorene, [alpha]-naphthyl isothiocyanate, or 2[image]-4[image]-dimethyl-4-dimethylaminoazobenzene. Nuclear counts, nuclear N, DNA and RNA, and phospholipids were determined at intervals during the feeding periods. Increased values of chemical constituents per parenchymal cell were obtained with feeding the carcinogen 2-acetamidofluorene, but not with the other 2 substances which are non-carcinogenic. The incorporations in vitro of [C14]glycine into nuclear protein. [C14]orotic acid into nuclear RNA, and [C14] adenine into nuclear nucleic acid were studied during the feeding periods. The only clear change obtained was a fall in the orotic acid and adenine incorporation during the feeding of 2-acetamidofluorene. The conclusion is drawn that, whereas chemical hepatocarcinogenesis is always accompanied by an increased chemical composition of parenchymal cell nuclei, the mechanism for this increase varies according to the carcinogen administered.