Comparative metabolism and fate of fenvalerate in Japanese quail (Coturnix coturnix japonica) and rats (Rattus norwegicus)

Abstract

Japanese quail were administered 100 mg/kg chlorophenyl-labeled [UC] fenvalerate, a-cyano-3phenoxybenzyl 2-(4-chlorophenyl)isovalerate, for study of its distribution, elimination, and metabolism. Ninety percent of the administered dose was eliminated in the excreta within the first 24 h. In addition to fenvalerate, the following metabolites were present: benzeneacetic acid, 4-chloro-a-(l-methylethyl)-, cyano(3-phenoxy-4-hydroxyphenyl)methyl ester [4'-OH-fenvalerate]; benzeneacetic acid, 4-chloro-a-(1-methylethyl)-, (aminocarbonyl)(3-phenoxyphenyl)methyl ester [CONH2-fenvalerate]; 4-chloro-a-(lmethylethyl)benzeneacetic acid [Cl-V acid]; 4-chloro-a-(2-hydroxy-1-methylethyl)benzeneacetic acid [4-OH-C1-V acid].In time course studies radiocarbon peaked at 3 h (9 pg/g) in the liver and gradually declined, while in the blood it peaked within 2 h and fell quickly to an equilibrium value of 1.5 pg/mL blood. In liver microsomal and isolated heptatocyte preparations of Japanese quail and rat, the following metabolites were identified: Cl-V acid, 4-OH-C1-V acid, 4'-OH-fenvalerate, CONH2-fenvalerate. Oxidation was found to be the predominant route of degradation either pre-or posthydrolysis of the parent compound. Rapid excretion, lesser absorption, and faster metabolism probably explain the lower toxicity of fenvalerate to birds compared to rats.

Comparative Toxicology of the Pyrethroid Insecticides

“…Oxidations primarily occur at the geminal dimethyl groups and on the phenoxy ring (Kaneko et al 1981;Mumtaz and Menzer 1986;Lee et al 1986). Hydrolysis of the ester linkage is also an important step toward detoxification and mobilization of pyrethroid residues in the mammalian body (Ruzo et al 1978), and substrate suitability has been evaluated in vitro (Soderlund and Casida 1977).…”

“…The disposition offenvalerate has been studied in both Japanese (Mumtaz and Menzer 1986) and bobwhite quail (Bradbury 1982). Bradbury (1982) orally administered [aromatic-3 H]fenvalerate to 3-and 16-w-old birds at a rate of 1.5 mg/kg/day for 14 d. Excretion offenvalerate equivalents was not significantly different between age groups, and within 24 h approximately 75% of the initial radiolabel was excreted.…”

“…Twenty-four h after the last dose, approximately 10% of the fenvalerate equivalents remained in the carcass. Mumtaz and Menzer (1986) treated Japanese quail orally with a single 100 mg/kg dose of [chlorophenyl-14C]fenvalerate. Within 12 h postdose, 84 to 97% of the administered radiocarbon was recovered in the excrement, and by 72 h virtually 100% was eliminated.…”

“…Metabolites are usually eliminated as alcohols, acids, or phenols either free or as conjugates. Detailed studies of avian metabolism are available for cis-and trans-permethrin (Gaughan et al 1978b), fenvalerate (Mumtaz andMenzer 1986, Akhtar 1983), and fluvalinate (Staiger et al 1982).…”

Metabolism and Bioaccumulation of Fenvalerate and its Metabolites in Rat Organs

“…This result indicates that fenvalerate has undergone hydrolytic ester cleavage in vivo as the first step of biodegradation. Formation of the metabolite PI has also been observed in mice and quails, both in vivo and in vitro as a major product (Kaneko et al, 1981;Mumtaz and Menzer, 1986). The IR spectrum of metabolite PII did not show characteristic peaks in the region of 1148 and 1750/cm, indicating absence of the gem-dimethyl and ester groups, respectively.…”