title: Control of ecdysteroidogenesis in prothoracic glands of insects: a review.
abstract: The very first step in the study of the endocrine control of insect molting was taken in 1922. Stefan Kopec characterized a factor in the brain of the gypsy moth, Lymantria dispar which appeared to be essential for metamorphosis. This factor was later identified as the neuropeptide prothoracicotropic hormone (PTTH), the first discovery of a series of factors involved in the regulation of ecdysteroid biosynthesis in insects. It is now accepted that PTTH is the most important regulator of prothoracic gland (PG) ecdysteroidogenesis. The periodic increases in ecdysteroid titer necessary for insect development can basically be explained by the episodic activation of the PGs by PTTH. However, since the characterization of the prothoracicostatic hormone (PTSH), it has become clear that in addition to 'tropic factors', also 'static factors', which are responsible for the 'fine-tuning' of the hemolymph ecdysteroid titer, are at play. Many of these regulatory factors are peptides originating from the brain, but also other, extracerebral factors both of peptidic and non-peptidic nature are able to affect PG ecdysteroidogenesis, such as the 'classic' insect hormones, juvenile hormone (JH) and the molting hormone (20E) itself. The complex secretory pattern of ecdysteroids as observed in vivo is the result of the delicate balance and interplay between these ecdysiotropic and ecdysiostatic factors.
authors.affiliation: Department of Animal Physiology and Neurobiology, K.U. Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Marchal
authors.forename: Hans Peter
authors.initials: HP
authors.lastname: Vandersmissen
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Badisco
authors.forename: Sandrien
authors.initials: S
authors.lastname: Van de Velde
authors.forename: Heleen
authors.initials: H
authors.lastname: Verlinden
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Iga
authors.forename: Pieter
authors.initials: P
authors.lastname: Van Wielendaele
authors.forename: Roger
authors.initials: R
authors.lastname: Huybrechts
authors.forename: Gert
authors.initials: G
authors.lastname: Simonet
authors.forename: Guy
authors.initials: G
authors.lastname: Smagghe
authors.forename: Jozef
authors.initials: J
authors.lastname: Vanden Broeck
mesh_terms: D000818:Animals; D026461:Ecdysteroids / Q000378:metabolism*; D004702:Endocrine Glands / Q000378:metabolism*; D007301:Insect Hormones / Q000096:biosynthesis* / Q000378:metabolism; D007313:Insecta / Q000378:metabolism*
chemical_list: D026461:Ecdysteroids; D007301:Insect Hormones