RESUMO
Propoxur is among the most popular insect control agents in subtropical countries such as Taiwan. As a member of the N-methylcarbamate insecticide group, propoxur is notorious for its potential for conversion into highly genotoxic N-nitroso derivatives. Due to the fact that the stomach has been identified as the major target for N-nitroso N-methylcarbamates, this investigation used a human gastric cell line, SC-M1, in order to obtain results pertinent to the authentic adverse effects of this compound on human health. This report reveals that at dose levels inhibiting < or = 10% cell growth, a 2-h pulsed treatment of N-nitroso propoxur induced significant amounts of DNA damage. Most of the damaged DNA was repaired within 24 h after treatment removal, such that an outcome with a significant induction of chromosomal aberrations was not observed. Gene mutations and anchorage independence, on the other hand, were significantly induced by this same treatment. In conclusion, exposure to low doses of N-nitroso propoxur is not cytotoxic nor clastogenic, nevertheless, has the potential to increase genetic instability and, possibly as a result, to enhance the malignant potential of treated cells. We suggest that although the damaged DNA was repaired during the transient G2/M arrest period, it was probably not done in an appropriate way which would preserve the original genetic stability.
Assuntos
Mucosa Gástrica/metabolismo , Mutagênicos/toxicidade , Propoxur/análogos & derivados , Idoso , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Ciclo Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Aberrações Cromossômicas/efeitos dos fármacos , Ensaio Cometa , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/efeitos da radiação , Citometria de Fluxo , Histonas/biossíntese , Histonas/genética , Humanos , Hipoxantina Fosforribosiltransferase/genética , Inseticidas/toxicidade , Cinética , Masculino , Testes de Mutagenicidade , Propoxur/toxicidade , Estômago/citologia , Raios UltravioletaRESUMO
The aim of this work was to investigate whether the pesticide propoxur and its nitroso derivative nitroso-propoxur increased the frequencies of sister-chromatid exchanges and micronuclei in human lymphocytes in vitro. The results show that both chemicals were genotoxic in the tested system.
Assuntos
Mutagênicos , Propoxur/análogos & derivados , Propoxur/toxicidade , Ciclo Celular , Células Cultivadas , Distribuição de Qui-Quadrado , Humanos , Linfócitos/efeitos dos fármacos , Micronúcleos com Defeito Cromossômico/efeitos dos fármacos , Troca de Cromátide Irmã/efeitos dos fármacosRESUMO
Nitrosation of the carbamate insecticide propoxur at pH 3 and 37 degrees C was determined colorimetrically and found to be time- and sodium nitrite concentration-dependent. Nitrosated propoxur was mutagenic when exposed to the seeds of the higher plant Arabidopsis thaliana but the formation of nitrosopropoxur, the presumed mutagen, was inhibited by humic acids, para-aminobenzoic acid and ascorbic acid. These agents also reduced the mutagenicity of preformed nitrosopropoxur.
