title: Structure-function analysis of Lymantria testis ecdysiotropin: a search for the active core.
abstract: A structure-function study was performed on the synthetic 21 residue neuropeptide, Lymantria testis ecdysiotropin (LTE), originally isolated from brains of Lymantria dispar pupae. The peptide induces ecdysteroid synthesis by testis sheaths of various lepidopteran species. LTE, as well as synthetic LTE 1-11, 11-21, and 11-15, stimulated synthesis in larval and pupal testes of Lymantria dispar at concentrations of 10(-9) to 10(-15) M; LTE 16-21 was weakly active, and an elongated LEU-LTE was inhibitory to synthesis at all but extremely low concentrations (10(-15) M). Since the sequence and polarity of residues in LTE 1-11, 11-15, and 11-21 are quite different, several parts of the molecule must activate receptors which initiate the cascade, resulting in ecdysiogenesis in Lepidopteran testes.
authors.affiliation: Insect Neurobiology and Hormone Laboratory, U.S. Department of Agriculture, Beltsville, Maryland 20705, USA. mloeb@asrr.arsusda.gov
authors.forename: M J
authors.initials: MJ
authors.lastname: Loeb
authors.forename: J
authors.initials: J
authors.lastname: Kochansky
authors.forename: R M
authors.initials: RM
authors.lastname: Wagner
authors.forename: C W
authors.initials: CW
authors.lastname: Woods
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D026461:Ecdysteroids; D006062:Gonadotropins / Q000737:chemistry* / Q000494:pharmacology / Q000502:physiology; D007301:Insect Hormones / Q000096:biosynthesis / Q000737:chemistry* / Q000494:pharmacology / Q000502:physiology; D007814:Larva / Q000737:chemistry / Q000378:metabolism; D008297:Male; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009036:Moths / Q000737:chemistry* / Q000378:metabolism; D009479:Neuropeptides / Q000737:chemistry* / Q000494:pharmacology / Q000502:physiology; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000494:pharmacology; D011679:Pupa / Q000737:chemistry / Q000378:metabolism; D011863:Radioimmunoassay; D017421:Sequence Analysis; D013256:Steroids / Q000096:biosynthesis; D013329:Structure-Activity Relationship; D013737:Testis / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D045165:Testosterone Congeners / Q000138:chemical synthesis / Q000494:pharmacology
chemical_list: D026461:Ecdysteroids; D006062:Gonadotropins; D007301:Insect Hormones; D009479:Neuropeptides; D010446:Peptide Fragments; D013256:Steroids; D045165:Testosterone Congeners; C108029:ecdysiotropin