title: Juvenile hormone regulates the steroidogenic competence of Manduca sexta prothoracic glands.
abstract: The acquisition of steroidogenic competence by prothoracic glands of last instar Manduca sexta larvae is regulated by juvenile hormone (JH). Topical treatment of pre-commitment larvae with JH I or (7S)-hydroprene (a JH analog) delays development by increasing the time to pupal commitment and wandering. Prothoracic gland competence is suppressed in JH-treated larvae: Unstimulated and prothoracicotropic hormone (PTTH)-stimulated rates of in vitro ecdysone secretion are decreased relative to rates of secretion by competent glands. (7S)-Hydroprene also suppresses the competence of glands in head-ligated pre-commitment larvae, suggesting the hormone acts directly on the glands. Two results indicate PTTH plays a role in controlling competence, and that JH regulates competence indirectly by inhibiting PTTH release: (1) head-ligation prevents the acquisition of full competence, and (2) cAMP levels are elevated in glands from JH-treated larvae. Thus, the decrease in the JH titer that precedes pupal commitment in Manduca is permissive for the acquisition by prothoracic glands of steroidogenic competence.
authors.affiliation: Department of Biology, University of North Carolina, Chapel Hill 27599-3280.
authors.forename: R D
authors.initials: RD
authors.lastname: Watson
authors.forename: W E
authors.initials: WE
authors.lastname: Bollenbacher
mesh_terms: D000818:Animals; D000242:Cyclic AMP / Q000032:analysis; D004440:Ecdysone / Q000096:biosynthesis*; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D007605:Juvenile Hormones / Q000494:pharmacology* / Q000502:physiology; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D007915:Lepidoptera / Q000502:physiology*; D009036:Moths / Q000502:physiology*; D013256:Steroids / Q000096:biosynthesis; D013909:Thorax / Q000166:cytology / Q000187:drug effects*
chemical_list: D005231:Fatty Acids, Unsaturated; D007605:Juvenile Hormones; D013256:Steroids; D004440:Ecdysone; C006481:ethyl-3,7,11-trimethyl-2,4-dodecadienoate; D000242:Cyclic AMP