title: Putative involvement of crustacean hyperglycemic hormone isoforms in the neuroendocrine mediation of osmoregulation in the crayfish Astacus leptodactylus.
abstract: This study investigates the involvement of eyestalk neuroendocrine factors on osmoregulation in the crayfish Astacus leptodactylus maintained in freshwater. Eyestalk removal was followed by a significant decrease in hemolymph osmolality and Na(+) concentration and by a 50% increase in mass after one molting cycle. Several neurohormones have been isolated from the sinus gland through high-performance liquid chromatography (HPLC), and different crustacean hyperglycemic hormone (CHH)-related peptides, including stereoisomers (L-CHH and D-Phe(3) CHH), have been identified by direct enzyme-linked immunosorbent assay (ELISA). A glucose quantification bioassay demonstrated a strong hyperglycemic activity following injection of the immunoreactive chromatographic fractions and showed that the D-Phe(3) CHH was the most efficient. Destalked crayfish were then injected with purified CHH HPLC fractions. The D-Phe(3) CHH fraction significantly increased the hemolymph osmolality and Na(+) content 24 h after injection. Two other CHH-related peptides caused a smaller increase in Na(+) concentration. No significant variation was observed in hemolymph Cl(-) concentration following injection of any of the CHH isoforms. These results constitute the first observation of the effects of a CHH isoform, specifically the D-Phe(3) CHH, on osmoregulatory parameters in a freshwater crustacean. The effects of eyestalk ablation and CHH injection on osmoregulation and the identification of different CHH-related peptides and isoforms in crustaceans are discussed.
authors.affiliation: Laboratoire Génome, Populations, Interactions, Adaptation, UMR 5000, Equipe Adaptation Ecophysiologique et Ontogenèse, Université Montpellier II, Place E Bataillon, CP 092, 34095 Montpellier Cédex 05, France.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Serrano
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Blanvillain
authors.forename: Daniel
authors.initials: D
authors.lastname: Soyez
authors.forename: Guy
authors.initials: G
authors.lastname: Charmantier
authors.forename: Evelyse
authors.initials: E
authors.lastname: Grousset
authors.forename: Fabien
authors.initials: F
authors.lastname: Aujoulat
authors.forename: Céline
authors.initials: C
authors.lastname: Spanings-Pierrot
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D060829:Arthropod Proteins; D003400:Astacoidea / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006458:Hemolymph / Q000737:chemistry; D007447:Invertebrate Hormones; D008845:Microinjections; D009419:Nerve Tissue Proteins / Q000302:isolation & purification / Q000378:metabolism*; D009490:Neurosecretory Systems / Q000378:metabolism; D020033:Protein Isoforms / Q000378:metabolism; D014882:Water-Electrolyte Balance / Q000502:physiology*
chemical_list: D060829:Arthropod Proteins; D007447:Invertebrate Hormones; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; C015947:hyperglycemic hormone, crustacean