Alkylation of guanine in mice in vivo by organophosphorus insecticides. I. Trichlorphone and butonate

Dedek, W.; Löhs, Karlheinz; Fischer, Gerhard W.; Schmidt, Reiner

doi:10.1016/0048-3575(76)90028-6

Cited by 17 publications

(6 citation statements)

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“…Nevertheless, the current evidence strongly indicates a need for caution in the interpretation of such data and it is already clear that the excretion of radiolabelled 3methyladenine or 7-methylguanine cannot be employed as evidence for the methylation of adenine or guanine moieties in the nucleic acids of animals exposed to methyl-labelled methylating agents. Similar considerations apply to the work of Dedek et al (1976) who have reported that the treatment of mice with large doses of methyllabelled trichlorphon or butonate resulted in the excretion of radio-labelled 7-methylguanine in their urine. These workers have also reported the presence of radiolabelled 7-methylguanine moieties in the combined RNA and DNA fractions from certain organs of these mice.…”

Section: W-o\ /Psupporting

confidence: 57%

“…2) provides the major route leading, ultimately, to the excretion of endogenously synthesised 7-methyl-guanine in urine. Consequently, the analytical procedures used by Dedek et al (1976) did not discriminate between spontaneous and natural incorporation of label into 7-methylguanine moieties in RNA or into urinary 7-methylguanine. As stated above, such differentiation is most readily achieved by choosing targets that yield products for which no biosynthetic pathway exists.…”

Section: W-o\ /Pmentioning

confidence: 99%

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Alkylation of DNA by Organophosphorus Pesticides

Wooder

Wright

1981

Acta Pharmacologica et Toxicologica

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Methods for the detection of in vivo alkylation of nucleic acids are discussed. Alkylation of mammalian DNA at N‐7 of guanine provides the most sensitive and least equivocal evidence of methylation by an exogenous chemical or its metabolite. No 7‐methylguanine was detected in the combined DNA from the lungs, livers, hearts, brains, kidneys, testes and spleens from 20 rats exposed to 0.064 μg l‐1 of [Me‐14C]‐dichlorvos at a specific radioactivity of 113 Ci mol‐1 for 12 hrs.

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Section: W-o\ /Psupporting

confidence: 57%

Section: W-o\ /Pmentioning

confidence: 99%

Alkylation of DNA by Organophosphorus Pesticides

Wooder

Wright

1981

Acta Pharmacologica et Toxicologica

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“…Thus, in the intestine the actual level of dichlorvos is somewhat higher than about 1 % in the blood (relative to metrifonate), as already shown following subcutaneous injection to pigs of metrifonate by Schwarz & Dedek (1965). The methylating potential of metrifonate to NBP amounts 4-6% only of that of dichlorvos in different solvents (Bedford & Robinson 1972;Dedek et al 1976). The physico-chemical properties of the two compounds, mainly the octanoll water partition coefficient (log P 0.57 and 1.46 for metrifonate and dichlorvos, respectively) and the half-life in a range of up t o 30 min.…”

Section: Discussionmentioning

confidence: 99%

“…and butonate (Dedek et a/. 1976), but a significantly longer half-life was found for high doses of dimethoate (Dedek, unpublished results).…”

Section: I40mentioning

confidence: 94%

Guanine N⁷‐Alkylation in Mice in Vivo by Metrifonate – Discussion of Possible Genotoxic Risk in Mammals

Dedek¹

1981

Acta Pharmacologica et Toxicologica

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Following intraperitoneal administration to male mice (strain AB Jena/Halle) of 14CH3‐labelled metrifonate, 22 Ci/mol, in dosages of 0.48, 0.40 and 0.065 mmol/kg, DNA from liver and kidneys was analysed for 14C in N‐7 methylguanine (7‐MeG). The extent of methylation in liver was found to be maximal at 6 hrs after injection in amounts of 6–8 and 0.8 μ mol 7‐MeG/mol guanine for the high and the low dose, corresponding to a covalent binding index CB14–5. The half‐life of excretion of 7‐MeG was 5 hrs for the high and 15 hrs for the low dose. The extent of methylation at 0–6 of guanine was estimated to be around 0.002–0.01 μmol 0–6 MeG/mol guanine. Data from references concerning methyl methanesulfonate and dimethyl sulfate are compared with those of metrifonate and the genotoxic response of methylating and non‐methylating metabolites is discussed.

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“…Mitodepression has been seen to be related to the phosphorylating and alkylat ing properties of a chemical (Lofroth et al 1969, Bedford and Robinson 1972, Rosenkranz and Rosenkranz 1972, Dedek et al 1976. Metasystox-R is having both phosphate as well as alkyl groups.…”

Section: Discussionmentioning

confidence: 99%

Mutagenic studies on the insecticide Metasystox-R with Allium cepa.

Pandita

1986

CYTOLOGIA

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Metasystox-R is an organophosphate systemic and contact insecticide. It is being indiscriminately used in some parts of India for the control of sap-feeding insects and mites. Metasystox-R has been shown to be mutagenic by Escherichia coil K12 (Mohn 1973, Wild 1975, Chinese hamster V79 cells sister-chromatid exchange test (Chen et al. 1982), and Ames Salmonella test, Schmid's micronucleus test and human lymphocyte sister-chromatid exchange test (Pandita 1983). Besides these tests the insecticide was found to inhibit in vitro DNA polymerization and transfection of Mycobacteriophage 13 DNA (Pandita 1985). There is no report regarding the effect of Metasystox-R on plant genetic system. With this inten tion studies were made to find the effect of Metasystox-R on seed germination, gametogenic cells, somatic cells and pollen fertility.As the pesticides can be converted in the plant systems (Plewa 1978) it was felt necessary to carry the progeny test in order to monitor sequentially the genetic damage at different stages of plant growth.The study reported herein provides information about the effect of insecticide on seed germination, mitotic index, chromotoxicity, 2C DNA content and pollen fertility. Materials and methodsThe chemistry and source of Metasystox-R have been described earlier (Pandita 1983). The same lot was used for the present study. Seeds and bulbs of a diploid (2n=16) AIlium cepa var. cepa were used as experimental material.To analyze the immediate genotoxic effects of Metasystox-R, the parts of the plant were directly exposed to the insecticide and the procedure followed is de scribed below. Studies on somatic cells: For somatic chromosome studies, the procedure described by Kihlman (1971) and Grant (1982) were adopted. Young bulbs with growing root tips of length 1-5cm were selected. Primary studies were made to find out the toxic doses which inhibit growth. Four subtoxic concentrations were applied for 24h.Root tip fixation, staining and slide preparation were done ac cording to the procedure described earlier (Pandita et al.

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Alkylation of guanine in mice in vivo by organophosphorus insecticides. I. Trichlorphone and butonate

Cited by 17 publications

References 50 publications

Alkylation of DNA by Organophosphorus Pesticides

Alkylation of DNA by Organophosphorus Pesticides

Guanine N⁷‐Alkylation in Mice in Vivo by Metrifonate – Discussion of Possible Genotoxic Risk in Mammals

Mutagenic studies on the insecticide Metasystox-R with Allium cepa.

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Alkylation of guanine in mice in vivo by organophosphorus insecticides. I. Trichlorphone and butonate

Cited by 17 publications

References 50 publications

Alkylation of DNA by Organophosphorus Pesticides

Alkylation of DNA by Organophosphorus Pesticides

Guanine N7‐Alkylation in Mice in Vivo by Metrifonate – Discussion of Possible Genotoxic Risk in Mammals

Mutagenic studies on the insecticide Metasystox-R with Allium cepa.

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Guanine N⁷‐Alkylation in Mice in Vivo by Metrifonate – Discussion of Possible Genotoxic Risk in Mammals