Hemolymph sugar homeostasis and starvation-induced hyperactivity affected by genetic manipulations of the adipokinetic hormone-encoding gene in Drosophila melanogaster.
Adipokinetic hormones (AKHs) are metabolic neuropeptides, mediating mobilization of energy substrates from the fat body in many insects. In delving into the roles of the Drosophila Akh (dAkh) gene, its developmental expression patterns were examined and the physiological functions of the AKH-producing neurons were investigated using animals devoid of AKH neurons and ones with ectopically expressing dAkh. The dAkh gene is expressed exclusively in the corpora cardiaca from late embryos to adult stages. Projections emanating from the AKH neurons indicated that AKH has multiple target tissues as follows: the prothoracic gland and aorta in the larva and the crop and brain in the adult. Studies using transgenic manipulations of the dAkh gene demonstrated that AKH induced both hypertrehalosemia and hyperlipemia. Starved wild-type flies displayed prolonged hyperactivity prior to death; this novel behavioral pattern could be associated with food-searching activities in response to starvation. In contrast, flies devoid of AKH neurons not only lacked this type of hyperactivity, but also displayed strong resistance to starvation-induced death. From these findings, we propose another role for AKH in the regulation of starvation-induced foraging behavior.
Lee
Gyunghee
G
Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, USA.
Park
Jae H
JH
D000818:Animals; D001011:Aorta / Q000196:embryology; D001921:Brain / Q000378:metabolism; D002241:Carbohydrates / Q000737:chemistry*; D002940:Circadian Rhythm; D003433:Crosses, Genetic; D004305:Dose-Response Relationship, Drug; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism*; D005247:Feeding Behavior; D017930:Genes, Reporter; D006458:Hemolymph / Q000378:metabolism*; D017403:In Situ Hybridization; D007301:Insect Hormones / Q000235:genetics*; D007814:Larva / Q000378:metabolism; D050356:Lipid Metabolism; D008957:Models, Genetic; D009474:Neurons / Q000378:metabolism; D009842:Oligopeptides / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives*; D013909:Thorax / Q000196:embryology; D013997:Time Factors; D019076:Transgenes
D002241:Carbohydrates; D007301:Insect Hormones; D009842:Oligopeptides; C044833:adipokinetic hormone; D011761:Pyrrolidonecarboxylic Acid