In vivo and in vitro metabolism of fipronil by larvae of the European corn borer Ostrinia nubilalis

Eric W. Durham, Blair D. Siegfried, Michael E. Scharf

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


In vivo and in vitro metabolism of[14C]fipronil was examined in a susceptible European corn borer (Ostrinia nubilalis, Hübner) laboratory strain. [14C]Fipronil penetrated the larval integument slowly, with 71.5% of the applied radioactivity recovered from surface rinses 24h after topical application. Despite this slow penetration, radioactivity was detected in both the excrement and internal organo-soluble fractions. Radioactivity in the internal aqueous fraction and tissue pellet accounted for less than 0.8% of total radioactivity. The in vivo studies suggest that fipronil oxidation to its sulfone metabolite is the major route of metabolic conversion. In vitro studies were performed using subcellular microsomal fractions isolated from European corn borer larval midguts. Cytochrome P450-dependent monooxygenase activity (methoxyresorufin O-demethylase) was consistently observed in midgut preparations, and formation and detection of the sulfone metabolite in the same midgut preparations was also NADPH-dependent and inhibited by piperonyl butoxide. In vitro metabolism results indicate microsomal monooxygenases are responsible for the conversion of fipronil to its sulfone form in the European corn borer.

Original languageEnglish (US)
Pages (from-to)799-804
Number of pages6
JournalPest Management Science
Issue number8
StatePublished - 2002

All Science Journal Classification (ASJC) codes

  • Agronomy and Crop Science
  • Insect Science


Dive into the research topics of 'In vivo and in vitro metabolism of fipronil by larvae of the European corn borer Ostrinia nubilalis'. Together they form a unique fingerprint.

Cite this