RH 5849, a Nonsteroidal Ecdysone Agonist: Effects on Larval Lepidoptera

Abstract

The ecdysone agonist RH 5849 (1,2-dibenzoyl-1-tert-butylhydrazine) causes the premature initiation of molting at all stages of larval development of the tobacco hornworm, Manduca sexta. This phenomenon occurs without an increase in the endogenous ecdysone (20-hydroxyecdysone) titers. RH 5849 likewise provokes the initiation of molting in larval abdomens in the absence of a source of endogenous hormone. Although substantially less active than 20-hydroxyecdysone in vitro, RH 5849 was 30 to >670 times as active as the authentic molting hormone in bioassays with isolated larval abdomens or intact hornworms. This reversal in potency can be attributed to the superior transport properties and metabolic stability of RH 5849 relative to 20-hydroxyecdysone. Thus RH 5849 and its analogs are relatively persistent ecdysone agonists that halt feeding in larval lepidoptera by forcing an ultimately lethal, developmentally premature molt.

Induction of an inactivation pathway for ecdysteroids in larvae of the cotton leafworm, Spodoptera littoralis

“…20-Hydroxyecdysone was a more effective inducer than ecdysone, suggesting that ecdysone must first undergo 20-hydroxylation in order for it to exhibit inductive activity. The effectiveness of RH 5849 may, in part, be a consequence of its lower metabolism and/or excretion (Wing, 1988;Wing et al, 1988). Evidence has been furnished for the intermediacy of the aldehyde (IV) in the conversion of 26-hydroxyecdysone (III) into the corresponding ecdysonoic acid (V) as indicated in Scheme 1.…”

“…We now report that administration of ecdysone, 20-hydroxyecdysone or RH 5849, a non-steroidal ecdysteroid agonist (Wing, 1988;Wing et al, 1988), to sixth-instar larvae of the cotton leafworm, Spodoptera littoralis, leads to induction of ecdysteroid 26-hydroxylase activity, but not of the 20-hydroxylase activity.…”

QSAR for Binding Affinity of Substituted Dibenzoylhydrazines to Intact Sf-9 Cells

“…1). 2,3) Some DBHs such as tebufenozide ( 6) and halofenozide ( Fig. 1: X n ϭH, Y n ϭ4-Cl) 7) are available on the market to control lepidopteran and other pest insects.…”

Endocrine Disrupting Compounds in Lotic Ecosystems: A Review on Its Occurrence, Sources and Effects on Chironomus riparius

“…Tebufenozide is a diacylhydrazine moult-inducing insecticide that has been developed for the control of larval lepidopteran pests in agriculture including forest and fruit-crops [57]. This compound is a non-steroidal ecdysone agonist that mimics natural moulting hormones, which contain, mainly, 20-OH ecdysone in larval insect.…”