title: Sterol metabolism in the tobacco hornworm, Manduca sexta--a review.
abstract: A number of intermediates involved in the dealkylation and conversion of the major C28 and C29 phytosterols to cholesterol in insects were first isolated and identified in studies with the tobacco hornworm, Manduca sexta, carried out in our laboratory. We also investigated the effects of a variety of known sterol metabolism inhibitors in Manduca, particularly those affecting the delta 24-sterol reductase enzyme, and synthesized and tested a number of new inhibitors as well. In-depth studies of ecdysteroids in Manduca during embryogenesis and during pupal-adult development provided new information on molting hormone content, biosynthesis, and metabolism. In addition, this insect has been utilized in the study of three specific enzyme systems of ecdysteroid metabolism, namely 20-monooxygenase, 3-epimerase, and phosphotransferase, which are critical to activation and deactivation of molting hormones in insects.
authors.affiliation: Insect Neurobiology & Hormone Laboratory, ARS, USDA, Beltsville, Maryland 20705, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Svoboda
authors.forename: G F
authors.initials: GF
authors.lastname: Weirich
mesh_terms: D000818:Animals; D000924:Anticholesteremic Agents / Q000494:pharmacology; D002784:Cholesterol / Q000096:biosynthesis*; D003640:Dealkylation; D026461:Ecdysteroids; D007301:Insect Hormones / Q000032:analysis; D018402:Manduca / Q000187:drug effects / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D010088:Oxidoreductases / Q000037:antagonists & inhibitors*; D010840:Phytosterols / Q000378:metabolism*; D013256:Steroids / Q000032:analysis
chemical_list: D000924:Anticholesteremic Agents; D026461:Ecdysteroids; D007301:Insect Hormones; D010840:Phytosterols; D013256:Steroids; D002784:Cholesterol; D010088:Oxidoreductases; C022673:delta 24-sterol reductase