Mutagenicity of nitrosodiethanolamine on Salmonella typhimurium

Nitrosodiethanolamine was examined in the Ames assay for bacterial mutagens. In absence of S9 activation a mutagenic effect was found.

Carcinogenicity of methylated derivatives of N-nitrosodiethylamine and related compounds in Sprague-Dawley rats

Five nitrosamines, which can be considered alkyl derivatives of N-nitrosodiethylamine, were tested for carcinogenicity by administration to Sprague-Dawley rats in drinking water at approximately equimolar concentrations. N-Nitrosodi-n-propylamine was a potent carcinogen but less so than N-nitrosodiethylamine and gave the same spectrum of tumors. N-Nitrosodiisopropylamine was very much weaker than N-nitrosodiethylamine and induced only tumors of the nasal turbinates in significant incidence. At the doses given, neither N-nitrosodiisobutylamine nor N-nitrosodi-sec-butylamine was significantly carcinogenic. In contrast, the cyclic nitrosamine N-nitrosohexamethyleneimine was equally potent with N-nitrosodiethylamine and gave the same spectrum of tumors in liver, esophagus, and nasal turbinates. The results support the concept that oxidation at the alpha carbon atom of nitrosamines is a significant step in carcinogenesis.

Relative carcinogenic effectiveness of derivatives of nitrosodiethylamine in rats

The carcinogenicity of five derivatives of nitrosodiethylamine was compared with that of the parent compound by p.o. administration to rats. All were less potent than was nitrosodiethylamine. When nitrosobis(2-methoxyethyl)amine and nitrosobis(2-ethoxyethyl)amine were administered at equimolar doses in drinking water, there was a high incidence of liver tumors, but the animals died later than they did after nitrosodiethylamine treatment, which also induced esophageal tumors. Nitrosoiminodipropionitrile and nitrosobis(2,2-diethoxyethyl)amine failed to induce tumors at the same dose level. Nitrosobis(2-chloroethyl)amine was administered in oil by gavage at a dose lower than that of nitrosodiethylamine and produced a much weaker tumor response; 5 of 15 treated rats had forestomach papillomas, and 1 had olfactory adenocarcinoma and no other induced tumors.

Urinary excretion of N-nitrosodiethanolamine administered orally to rats

N-Nitrosodiethanolamine (NDE1A) was administered by gavage to male rats in single doses of 1000, 500 and 100 mg/kg body wt. More than 70% of a given dose was excreted unchanged in the urine, essentially within the first 24 h after exposure. This high excretion rate might explain the relatively low carcinogenic potential of NDE1A, and also offers a possible method of monitoring exposure to this compound under occupational and/or environmental conditions.

Vinylethylnitrosamine: a potent respiratory carcinogen in Syrian hamsters

Vinylethylnitrosamine (VEN), an alpha-beta unsaturated analogue of diethylnitrosamine (DEN), which may be formed by the enzymic conversion necessary for carcinogenesis, was synthesized and its biologic effect was examined by sc administration to Syrian hamsters. Distribution studies showed that the maximum amount of unaltered compound was found in various tissues 45 minutes after injection. The chemical was only partially excreted unchanged after 5 hours. Weekly treatment for life resulted in high incidence of malignant respiratory tract neoplasms with short latencies and in tumors of the upper digestive tract and pancreas. The effects of VEN were compared to those of the assumed parent compound, DEN.

Tumorigenic agents in unburned processed tobacco: N-nitrosodiethanolamine and 1,1-dimethylhydrazine

Two tumorigenic agents, N-nitrosodiethanolamine and 1,1-dimethylhydrazine, have been isolated from tobacco for the first time. The former, a reportedly weak hepatic carcinogen in rats, varied in amounts from a low of 0.1 ppb in flue-cured tobacco not treated with the herbicide MH-30, to a high of 173 ppb in Burley tobacco to which the herbicide had been applied prior to harvesting. MH-30 (maleic hydrazide) used by farmers to remove 'suckers' from tobacco plants, is commonly formulated as the diethanolamine salt. 1,1-Dimethylhydrazine, reported to induce tumors in mice, ranged in amounts from 60 to 147 ppb, except in the case of Burley tobacco where none was detected (detection limit: 0.1 ng). The source of the nitrosamine in the tobacco appears to be the MH-30, whereas that of dimethylhydrazine has not been determined.

Mutagenicity of N-alpha-acetoxyethyl-N-ethylnitrosamine and N,N-diethylnitrosamine in relation to the mechanisms of metabolic activation of dialkylnitrosamines

The mutagenicities of N-alpha-acetoxyethyl-N-ethylnitrosamine and N,N-diethylnitrosamine were compared in Drosophila for an assessment of the role of alpha-carbon ethyl oxidation in the toxicological activation of the amine. The relative genetic potencies of the two compounds were deduced from regression studies of the mutation frequencies on molar dose for the whole testicular tissue with respect to the induction of the overall X-chromosome recessives (lethals and visibles), representatives of the RNA genes (especially ribosomal DNA), and six specific euchromatic loci. Genetic activity per unit molar dose was invariably higher for the acetoxy compound than for the parent amine, but the two agents produced comparable mosaicism among corresponding mutational classes. This indicated that the same mutagenic reactive species were generated from the two agents, but more readily from the acetoxy derivative, which accorded with the hypothesis of nitrosamine metabolic activation through alpha-carbon alkyl hydroxylation. The differentials for the higher activity of the acetoxy compound varied between mutational classes: 20-fold for the X-chromosome recessives collectively or per locus, but only 5-fold for the specific ribosomal DNA deletions. These relationships indicated that the mutagenicities of these compounds were not entirely an outcome of DNA ethylation but were readily explicable on the basis of the additional generation of difunctional nitrosaldehydic metabolites, which were largely responsible for the induction of the ribosomal DNA deletions through DNA protein cross-link-age. The higher mutagenicity of the acetoxy compound relative to the parent amine on ribosomal DNA was in part countered by its much lower selectivity index for these genes. The possible relevance of these genetic features to the carcinogenicities of these compounds was considered.

Induction of renal pelvic tumours in Sprague-Dawley rats by di-isopropanolnitrosamine

Transitional cell papillomas and carcinomas of the renal pelvis were observed in Sprague-Dawley rats after subcutaneous (s.c.) treatment with di-isopropranolnitrosamine (DIPN). These tumours occurred unilaterally and appeared as early as 24 weeks after the commencement of treatment. The tumours frequently filled the entire renal pelvis and compressed the kidney parenchyma. The malignant neoplasms demonstrated infiltrative growth into the adjacent medullary parenchyma.