Metabolism of (+)-trans- and (+)-cis-resmethrin in rats

Ueda, Kenzo; Gaughan, Loretta C.; Casida, John E.

doi:10.1021/jf60197a022

Cited by 52 publications

(38 citation statements)

References 11 publications

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“…In accord with the in vitro studies, in vivo experiments revealed that ( + )-cis-resmethrin gave rise to at least two unidentified ester metabolites in rat feces (20). Feces of rats contained three ester metabolites (I-III) of (+) -cis-fenothrin which are never or hardly derived from (+) -transfenothrin.…”

Section: Metabolism In Mammalssupporting

confidence: 62%

“…An appreciable amount of tritium from allethronyl-3H (+ )-trans-chrysanthemumate was not recovered in the rat excreta (21,22). Incomplete excretion was also observed in the acid moiety of resmethrin, 70-73% of the radiocarbons being recovered during 6-day intervals (20). A substantial amount of the radioactivity was found in feces in every compound tested regardless of the dosage, and enterohepatic circulation may play some role, as in the case of resmethrin (17) and proparthrin (19) .…”

Section: Metabolism In Mammalsmentioning

confidence: 93%

“…As to the in vivo metabolism of acid moiety of the synthetic pyrethroids, few studies have so far been carried out (20). Interesting findings have been obtained, by Ueda et al (20), as shown in eqs.…”

Section: Metabolism In Mammalsmentioning

confidence: 98%

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Degradation, metabolism and toxicity of synthetic pyrethroids.

Miyamoto¹

1976

Environ Health Perspect

202

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Synthetic pyrethroidal compounds undergo biodegradation in mammals both oxidatively and hydrolytically, and depending on the type of compound, either of the pathways may predominate. Thus, (+) -or (±) -trans isomers of the chrysanthemumate ester of primary alcohols such as fenothrin, furamethrin, proparthrin, resmethrin, and tetramethrin (and possibly permethrin, too) are metabolized mainly through hydrolysis of the ester linkage, with subsequent oxidation and/or conjugation of the component alcohol and acid moieties. On the other hand, the corresponding (+ )-cis enantiometers and chrysanthemumate of secondary alcohols like allethrin are resistant to hydrolytic attack, and biodegraded via oxidation at various sites of the molecule. These rapid metabolic degradations, together with the presumable incomplete absorption from the gastrointestinal tract, would generally contribute to the low acute toxicity of synthetic pyrethroids.These compounds are neither skin irritants nor skin sensitizers, and inhalation toxicity as well as dermal toxicity are fairly low. Neither is teratogenic in rats, mice, and/or rabbits or mutagenic on various bacterial strains. Subacute and chronic feeding of higher amounts of the compounds to rats invariably causes some histopathological changes in liver; however, these are neither indicative nor suggestive of tumorigenicity.Based on existing toxicological information, the present recommended use patterns might afford sufficient safety margin on human population.However, in extending usage to agricultural pest control, much more extensive investigations should be forthcoming from both chemical and biological aspects, since there is scant information on the fate of these pyrethroids in the environment. Also several of the compounds may be very toxic to certain kinds of fish and arthropods.

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Section: Metabolism In Mammalssupporting

confidence: 62%

Section: Metabolism In Mammalsmentioning

confidence: 93%

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Degradation, metabolism and toxicity of synthetic pyrethroids.

Miyamoto¹

1976

Environ Health Perspect

202

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“…The less desirable properties of chlorinated hydrocarbon insecticides are associated with their lipophilicity and inert chemical structures so that they are stored in the fatty tissues of organisms rather than being metabolized and eliminated. Although pyrethroids are similar to the chlorinated hydrocarbons in some of their physical properties, much evidence from research in the past decade (59)(60)(61)(62)(63)(64)(65)(66)(67)(68) suggests that the structural features of pyrethroids render them susceptible to mammalian detoxification systems, so that by one or more of several possible pathways they are rapidly converted to more polar compounds and are excreted in the urine or feces.…”

Section: Physical Properties Of Pyrethroids and Other Insecticidesmentioning

confidence: 99%

Properties and applications of pyrethroids.

Elliott¹

1976

Environ Health Perspect

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Improved understanding of the factors determining the insecticidal activity, the mammalian toxicity, and the stability in air and light of natural and synthetic pyrethroids has led to a series of new compounds with a very favorable combination of properties. Their characteristicsinclude outstanding potency to insects, low toxicity to mammals associated with rapid metabolic breakdown and, in appropriate cases, adequate stability on plant surfaces even in bright sunlight. Initial tests indicate that even the more stable compounds are degraded rapidly in soil, so if the trials at present in progress reveal no toxicological or environmental hazards, within a few years synthetic pyrethroids should be available to control a wide range of domestic, veterinary, horticultural, agricultural, and forest pests at low rates of application.

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“…Thus, an elucidation of these features was undertaken using a pyrethroid insecticide tetramethrin [Neopynamin,3,4, MATERIALS AND METHODS…”

Section: Introductionmentioning

confidence: 99%

Metabolism and Placental Transfer of Stereoisomers of Tetramethrin Isomers in Pregnant Rats

et al. 1984

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isomers labeled with 14C in the acid moiety to 13-day pregnant rats at 300 mg/kg, the radiocarbon was rapidly eliminated into the urine and feces, and almost completely recovered within 7 days. The 14C tissue residue levels were very low with the four labeled preparations. The major metabolic reactions for the four isomers were cleavage of the ester linkage and oxidation at the isobutenyl group of the acid moiety. The traps isomers underwent ester cleavage to larger extents than the cis isomers. There were no significant differences in the 14C excretion, 14C tissue residue levels and the nature and amounts of metabolites between the [1 R]-and [1 RS]-traps isomers. The absorption in the gastrointestine, however, seemed to differ between the [1 R, cis]-and [1 RS, cis]-isomers, although once entering into the blood stream, the [1 R]-and [1 RS]-cis isomers appeared to receive the same matabolic fates. When 13-day pregnant rats were treated with single or 5 consecutive daily oral administrations of each of 14C-Neopynamin® (1 RS, traps/cis, 8/2) and Neopynamin Forte® (1 R, traps/ cis, 8/2) preparations labeled with 14C in the acid moiety at 300 mg/kg or 300 mg/kg/day, the radiocarbon transferred to the fetus were less than 0.004% of the dose and there were no significant differences in the 14C levels and the transfer ratio (14C tissue levels/14C maternal blood) for the fetus between the two preparations.Moreover, the major metabolites in the fetus and maternal blood with the two preparations were the same, and identified as chrysanthemic acids and their hydroxymethyl or carboxylic acid derivatives.

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Metabolism of (+)-trans- and (+)-cis-resmethrin in rats

Cited by 52 publications

References 11 publications

Degradation, metabolism and toxicity of synthetic pyrethroids.

Degradation, metabolism and toxicity of synthetic pyrethroids.

Properties and applications of pyrethroids.

Metabolism and Placental Transfer of Stereoisomers of Tetramethrin Isomers in Pregnant Rats

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