Metabolism of Pyriproxyfen. 2. Comparison of in Vivo Metabolism between Rats and Mice

Abstract

The metabolic fate of pyriproxyfen [4-phenoxyphenyl (RS)-2-(2-pyridyloxy]propyl ether, Sumilarv) was examined in rats and mice given single oral doses of [pyridyl-2,6-14C]-or \phenoxyphenyl-14C]pyriproxyfen at doses of 2 and 1000 mg/kg. The carbon-14 was excreted almost completely into urine and feces within 7 days after dosing and fecal excretion of carbon-14 predominated in both animals. Excretion of carbon-14 into feces and urine was, respectively, 84-97% and 4-12% of the dose in rats and 64-91% and 9-38% in mice. Major metabolic reactions of pyriproxyfen were (1) hydroxylation at the 4-position of the terminal phenyl ring, (2) hydroxylation at the 2-position of the terminal phenyl ring, (3) hydroxylation at the 5-position of the pyridyl ring, (4) dephenylation, (5) cleavage of ether linkages, and (6) conjugation of the resultant phenols with sulfuric acid or glucuronic acid. Although there was generally no marked difference in the metabolic profile of pyriproxyfen between the two species, significant sex-related differences were found in metabolic reactions 1, 3, and 6 in the rat but not in the mouse.

Effect of illumination on degradation of pyriproxyfen in water-sediment system

“…The good 14 C recovery of 89.5-102.9% was observed similarly to the dark study in a larger vessel, as shown in Tables 5 and 6. The partition of 14 C to sediment was more rapid under 36 R. Kodaka et al Journal of Pesticide Science illumination than in the dark control but the final distribution between water and sediment phases was similar.…”

“…Aqueous 14 C rapidly decreased to less than 40% after 2 days by partitioning to the bottom sediment. The amount of bound 14 Tables 3 and 4. HPLC analysis of the extracts from each phase showed differences in the distribution of I between the labels, most likely due to the heterogeneity of the water-sediment system.…”

TR4 and PPARγ activities are differentially modulated by pyriproxyfen

“…; Yoshino et al . ). Furthermore, we recently reported that PYR enhances adipogenesis of murine 3T3‐L1 pre‐adipocytes via upregulation of TR4 activity, although TR4 could be stimulated only at the low concentration of PYR (Choi & Kim ).…”

Pyriproxyfen promotes lipid accumulation in 3T3‐L1 adipocytes by enhancement of TR4 activity

“…Although several studies reported that JHs and JH‐like insecticides have some effects on mammalian physiology, little information is available on their roles in glucose and lipid metabolism in mammals (Yoshino et al . ). Adipose tissues are the major lipid storage site to control body lipid fluxes in response to energy requirements (Rosen & MacDougald ).…”

“…20-hydroxyecdysone (20E) is an essential insect molting hormone which is chemically closely related with mammalian 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) (Wurtz et al 2000). It has been reported that 20E has a variety of beneficial effects on mammalian physiology (Matsunaga et al 1995;Yoshino et al 1995Yoshino et al , 1996No et al 1996). Ecdysteroids showed suppressive effects on the hyperglycemia and stimulation of hepatic glucose consumption.…”