Comparative carcinogenicity of o-toluidine hydrochloride and o-nitrosotoluene in F-344 rats

Stephen S. Hecht, Karam El-Bayoumy, Abraham Rivenson, Emerich Fiala

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


o-Toluidine hydrochloride and one of its metabolites, o-nitrosotoluene, were administered in the diet (0.028 mol/kg diet) to 2 groups of 30 male F-344 rats for 72 weeks. o-Nitrosotoluene induced significantly more tumors of the bladder ( 16 30 rats) and liver ( 20 30) than did o-toluidine hydrochloride (bladder, 4 30; liver, 3 30). Both compounds induced comparable numbers of peritoneal tumors and fibroma of the skin and spleen. o-Toluidine hydrochloride induced more mammary tumors ( 13 30) than did o-nitrosotoluene ( 3 30). The results indicate that N-oxidation is important in the induction of bladder and liver tumors by these single ring compounds but that other mechanisms could be involved in the induction of peritoneal, skin, spleen and mammary tumors.

Original languageEnglish (US)
Pages (from-to)103-108
Number of pages6
JournalCancer Letters
Issue number1
StatePublished - 1982
Externally publishedYes

Bibliographical note

Funding Information:
This study was supported by National Cancer Institute Grant 26395. We thank Mr. Jeffrey Rigotty for his excellent technical assistance.


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