In vivo formation of nitrosocarbamates in the stomach of rats and guinea pigs

Journal Article · Sun Jan 01 04:00:00 EST 1984 · J. Toxicol. Environ. Health; (United States)

DOI:https://doi.org/10.1080/15287398409530580· OSTI ID:5946568

Rickard, R W; Dorough, H W

The N-nitrosocarbamates are potent mutagens and carcinogens and have been synthesized under acid conditions that prevail in the human stomach. However, it has never been documented that nitrosocarbamates are actually formed in vivo in the stomach of any mammalian species. Using /sup 14/C-labeled carbaryl and carbofuran, attempts were made to isolate the nitroso derivatives from the stomach contents of rats and guinea pigs treated orally with the carbamate and sodium nitrite. Only trace quantities of nitrocarbamate were recovered from the rat stomach, whereas 0.5 to 2.0% of the carbamate doses were isolated as the nitroso derivative from the contents of the guinea pig stomach. The rather low apparent yields resulted in part from the instability of the nitrosocarbamates and from absorption of the carbamate and/or nitrosocarbamate from the stomach. Higher rates of synthesis were indicated by incubating the carbamates with sodium nitrite in the presence of the stomach contents at 37/sup 0/C for 15 min. About 30% nitrosation occurred with the guinea pig and about 0.5% with the rat. The difference was attributed to the pH of the gastric contents. For the rat, the pH ranged from 3 to 5; gastric contents of the guinea pig had a pH between 1 and 2. Since the pH of the human stomach is also in the pH 1-2 range, it is likely that nitrosation of carbamates in humans would be very similar to that in the guinea pig. 21 references, 3 figures, 3 tables.

• Research Organization: Univ. of Kentucky, Lexington
• OSTI ID: 5946568
• Journal Information: J. Toxicol. Environ. Health; (United States), Journal Name: J. Toxicol. Environ. Health; (United States) Vol. 14:2-3; ISSN JTEHD
• Country of Publication: United States
• Language: English

Related Subjects

560305* -- Chemicals Metabolism & Toxicology-- Vertebrates-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALI METAL COMPOUNDS
ANIMALS
BIOSYNTHESIS
BODY
CARBAMATES
CARBON 14 COMPOUNDS
CARBONIC ACID DERIVATIVES
CARBOXYLIC ACID SALTS
CARCINOGENS
CHEMICAL REACTIONS
COMPARATIVE EVALUATIONS
DATA
DIGESTIVE SYSTEM
EXPERIMENTAL DATA
GASTROINTESTINAL TRACT
GUINEA PIGS
INFORMATION
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
METABOLISM
MUTAGENS
NITRATES
NITROGEN COMPOUNDS
NITROSO COMPOUNDS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
PH VALUE
RATS
RESPONSE MODIFYING FACTORS
RODENTS
SODIUM COMPOUNDS
SODIUM NITRATES
STOMACH
SYNTHESIS
TRACER TECHNIQUES
VERTEBRATES