title: Characterization of the adipokinetic hormone receptor of the anautogenous flesh fly, Sarcophaga crassipalpis.
abstract: Adipokinetic hormone (AKH) is an insect neuropeptide mainly involved in fat body energy mobilization. In flies (Phormia regina, Sarcophaga crassipalpis), bugs (Pyrrhocoris apterus) and cockroaches (Periplaneta americana) AKH was also demonstrated to be involved in the regulation of digestion. This makes AKH an important peptide for anautogenous female flies that need to feed on a supplementary protein meal to initiate vitellogenesis, the large scale synthesis of yolk proteins and their uptake by the developing oocytes. Flesh fly AKH, originally identified as Phormia terraenovae hypertrehalosemic hormone (PhoteHrTH), functions through activation of the AKH receptor (AKHR). This is a G protein-coupled receptor that is the orthologue of the human gonadotropin-releasing hormone receptor. Pharmacological characterization indicated that the receptor can be activated by two related dipteran AKH ligands with an EC50 value in the low nanomolar range, whereas micromolar concentrations of the Tribolium castaneum AKH were needed. Consistent with the energy mobilizing function of AKH, the receptor transcript levels were most abundant in the fat body tissue. Nonetheless, Sarcophaga crassipalpis AKHR transcript levels were also high in the brain, the foregut and the hindgut. Interestingly, the receptor transcript numbers were reduced in almost all measured tissues after protein feeding. These changes may enforce the use of ingested energy carrying molecules prior to stored energy mobilization.
authors.affiliation: Research Group of Insect Physiology and Molecular Ethology, KU Leuven, Naamsestraat 59, B-3000, Belgium.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Bil
authors.affiliation: Research Group of Insect Physiology and Molecular Ethology, KU Leuven, Naamsestraat 59, B-3000, Belgium.
authors.forename: Iris
authors.initials: I
authors.lastname: Timmermans
authors.affiliation: Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, B-3000, Belgium.
authors.forename: Heleen
authors.initials: H
authors.lastname: Verlinden
authors.affiliation: Research Group of Insect Physiology and Molecular Ethology, KU Leuven, Naamsestraat 59, B-3000, Belgium. Electronic address: Roger.Huybrechts@bio.kuleuven.be.
authors.forename: Roger
authors.initials: R
authors.lastname: Huybrechts
mesh_terms: D000595:Amino Acid Sequence; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D016466:CHO Cells; D003001:Cloning, Molecular; D003412:Cricetulus; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005260:Female; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D012313:RNA / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D058493:Sarcophagidae / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D018076:DNA, Complementary; D019476:Insect Proteins; D043562:Receptors, G-Protein-Coupled; D012313:RNA
keywords: Adipokinetic hormone; Adipokinetic hormone receptor; Anautogeny; Differential expression; Flesh fly; G protein-coupled receptor