Non‐steroidal ecdysteroid agonists: Tools for the study of hormonal action

Oberlander, Herbert; Silhacek, Donald L.; Porcheron, P.

doi:10.1002/arch.940280303

Cited by 78 publications

(43 citation statements)

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“…Similar decreases in weight gain in response to other analogues of RH-2485 were reported by Oberlander et al (1995), Smagghe et al (1995Smagghe et al ( , 1997 and Blackford & Dinan (1997a, b). Incomplete cocooning and unsuccessful pupation resulted in prepupa and larval-pupal intermediates (LPIs) leading to death in the treated larvae, are mainly due failure or incomplete shedding of old cuticle.…”

Section: Discussionsupporting

confidence: 84%

“…Cessation of feeding and precocious moulting in the larvae treated with RH-2485 were reported by Wing et al (1988) in Manduca sexta (L., 1763), Silhacek et al (1990) in Plodia interpunctella (Hübner, 1813), Darvas et al (1992) in Spodoptera littura (F., 1775), Smagghe & Degheele (1993) in Spodoptera exigua (Hübner, 1808) and Spodoptera exempta (Walker, 1858), Leondardi et al (1996) in Bombyx mori L., 1758, Retnakaran et al (1997) in Choristoneura fumiferana and Smagghe & Degheele (1994) in S. exigua. At low doses, suppression of weight gain after treatment with RH-5849 or tebufenozide was also reported by Oberlander et al (1995), Smagghe et al (1995Smagghe et al ( , 1997, Blackford & Dinan (1997a, b). Low amount of food intake in the larvae of Lacanobia oleracea (L., 1758) treated with RH-5849 and RH-5992 was considered as an important factor contributing to the decline in body weight (Blackford & Dinan 1997a).…”

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confidence: 62%

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Effect of RH-2485 on development, metamorphosis and synthesis of major proteins in female silkworm Bombyx mori

2010

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Toxicological data on silkworm Bombyx mori are quite comparable to those of other lepidopteran pest insects, therefore, it is considered as a suitable model for exploring effects of any new synthetic formulations. In this study, female V instar larvae of silk moth B. mori were chosen to evaluate the lethal and sublethal toxicity effects of RH-2485 (methoxyfenozide), a non-steroidal ecdysteroid agonist and to substantiate the ecdysteroid mimicking action of RH-2485 on ovary development, vitellogenin incorporation and egg production in isolated pupal abdomen (IPA). Probit analysis was carried out to find the median lethal dose (LD50) from 96 h cumulative mortality percent. Protein profile of haemolymph, fat body, ovary and eggs were separated in SDS-PAGE. Western blot analysis was carried out to confirm vitellogenin in the ovary. Sublethal effects on feeding, cocoon spinning, pupation, adult emergence and egg production were studied at doses of 1/5 th , 1/10 th and 1/20 th of LD50. Significant changes were observed in all these parameters at all three sublethal doses. The morphological effects were related to underlying biochemical changes by finding the changes in haemolymph, fat body, ovary and egg protein profile. Marked changes were observed in storage proteins (80 kDa) and 30 kDa proteins in the haemolymph at all three sublethal doses. The larvae that escaped the sublethal effects at a dose of 1/20 of LD50 and emerged as adults with malformed wings produced significantly lower number of eggs. The isolated pupal abdomen (IPA) treated with RH-2485 did not metamorphose into adult but the oocyte development and vitellogenesis were normal but the egg precursor processing was incomplete leading to failure in choriogenesis.

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Section: Discussionsupporting

confidence: 84%

supporting

confidence: 62%

Effect of RH-2485 on development, metamorphosis and synthesis of major proteins in female silkworm Bombyx mori

2010

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“…Although substantially less active than 20-hydroxyecdysone in various in vitro systems, RH-5849 is far more active and persistent in various in vivo assays, presumably owing to the analog's superior transport properties and metabolic stability (13,25). In fact, RH-5849 has been observed to have greater potency to induce ecdysone hydroxylating activities than 20-hydroxyecdysone and ecdysone (15,20).…”

mentioning

confidence: 99%

Induction of Enzymes Involved in Molting Hormone (Ecdysteroid) Inactivation by Ecdysteroids and an Agonist, 1,2-Dibenzoyl-1-tert-butylhydrazine (RH-5849)

Williams

Chen

Fisher

et al. 1997

Journal of Biological Chemistry

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Molting in insects is regulated by molting hormones (ecdysteroids). The major active hormone, 20-hydroxyecdysone, is formed by ecdysone 20-monooxygenase-catalyzed hydroxylation of ecdysone. During times of decreasing hormone titers, inactivation occurs by several routes including (i) 26-hydroxylation and further oxidation to the 26-oic acid, (ii) formation of various conjugates (e.g. phosphates), and (iii) in Lepidoptera in particular, ecdysone oxidase-catalyzed formation of 3-dehydroecdysteroid, which is reduced to 3-epiecdysteroid, followed by phosphotransferase-catalyzed formation of phosphate conjugates. Administration of the nonsteroidal ecdysteroid agonist RH-5849 (1,2-dibenzoyl-1-tert-butylhydrazine), but not 20-hydroxyecdysone, to tobacco hornworm (Manduca sexta) resulted in induction of midgut cytosolic ecdysone oxidase and ecdysteroid phosphotransferase activities. In addition, both 20-hydroxyecdysone and RH-5849 caused induction of ecdysteroid 26-hydroxylase activity in midgut mitochondria and microsomes, whereas 20-hydroxylase was induced to a lesser extent by 20-hydroxyecdysone in mitochondria and by either RH-5849 or 20-hydroxyecdysone in microsomes. Commensurate with induction of the enzymes by ecdysteroid and RH-5849 is a requirement for RNA and protein synthesis, without precluding indirect mechanisms. These results indicate that molting hormone stimulates at least one universal route of its own inactivation by inducing ecdysteroid 26-hydroxylase activity and are discussed in relation to an analogous phenomenon observed for vitamin D inactivation in vertebrates.Molting hormones (ecdysteroids) regulate molting in immature stages of insects (1). Conversion of ecdysone into the major active hormone 20-hydroxyecdysone occurs in certain peripheral tissues and is catalyzed by the cytochrome P450-dependent ecdysone 20-monooxygenase (2, 3). The activity of this enzyme undergoes developmental change, exhibiting a distinct peak during the final larval instar in several species (2, 4).Inactivation of ecdysteroids occurs by various reactions including conversion of ecdysteroid via the 26-hydroxy derivative into the 26-oic acid, formation of various conjugates (e.g. phosphates), and conversion into 3-epi(3␣-hydroxy)-ecdysteroids (5, 6). 3-Epiecdysteroid formation is prominent in lepidopteran midgut cytosol and involves ecdysone oxidase-catalyzed formation of 3-dehydroecdysteroid followed by NAD(P)H-dependent irreversible reduction to 3-epiecdysteroid, which may also be phosphorylated. The 3-dehydroecdysteroid may also undergo NAD(P)H-dependent reduction back to 3␤-hydroxy ecdysteroid (for reviews, see Refs. 3 and 7). These enzymatic activities in the midgut cytosol ( Fig. 1) also exhibit developmental changes (8, 9).In the tobacco hornworm (Manduca sexta), the subject of this investigation, midgut ecdysone 20-monooxygenase is localized in both mitochondrial and microsomal fractions (10). During development of the fifth instar, the midgut 20-monooxygenase undergoes a 50-fold increase in activity, temporally c...

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“…In other words, as potency has already been shown by the flight trials [53][54][55] , these locusts are no longer capable of sustained flight. The effects of Azadirachtin on a variety of different insect species have been described, and these effects are due mainly to a disturbance of the hormonal system of the insect by suppression of the concentration of haemolymph ecdysteroids and juvenile hormones [46,[56][57][58] . The active ingredient in neem, azadirachtin, interferes with the hormones involved in insect moulting.…”

Section: Decrease Of Adipokinetic Responsementioning

confidence: 99%

Effect of Different Neem Products on the Mortality and Fitness of Adult Schistocerca gregaria (Forskal)

Al-Fifi

2009

sci

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Abstract. Various neem products were tested against resting and flying Schistocerca gregaria. Two of the products namely neem Azal-F and the unclarified neem oil were obtained from the Company Trifolio, whereas neem oil enriched and pure neem oil, were a gift of Prof. Schmutterer (University of Giessen). The treatment during flight activity caused, for all products applied an increase of the mortality rate, except the neem oil enriched and pure neem oil of Giessen, up to 70 and 90% respectively. The same products, however, sprayed on resting locusts did not show any remarkable mortality. But this treatment reduced the fitness of the locusts in terms of their flight performance, as well as their adipokinetic potency. In consequence of this, it is to expect that neem treated locusts will not be able to cover long distances. That means the lipid mobilizing system necessary to provide the flight muscles with "fuel" (lipids) is disturbed severely.

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Non‐steroidal ecdysteroid agonists: Tools for the study of hormonal action

Cited by 78 publications

References 48 publications

Effect of RH-2485 on development, metamorphosis and synthesis of major proteins in female silkworm Bombyx mori

Effect of RH-2485 on development, metamorphosis and synthesis of major proteins in female silkworm Bombyx mori

Induction of Enzymes Involved in Molting Hormone (Ecdysteroid) Inactivation by Ecdysteroids and an Agonist, 1,2-Dibenzoyl-1-tert-butylhydrazine (RH-5849)

Effect of Different Neem Products on the Mortality and Fitness of Adult Schistocerca gregaria (Forskal)

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