Role of adipokinetic hormone in the circadian locomotory activity rhythms of Drosophila melanogaster

Adipokinetic hormones (AKH) are secreted in insects by a group of cells in the corpora cardiaca region of the brain. This neuropeptide primarily functions in the mobilization of energy sources for locomotion and flight. Diel changes in secretion of this hormone have been reported earlier. However, the precise links between the circadian clock system and AKH secretion and its impact on circadian locomotory rhythms have not been investigated. In this study, we used the fruit fly Drosophila melanogaster to investigate the role of AKH in circadian locomotor activity rhythms. We used several transgenic lines with AKH cells deficient  (AKH-CD), AKH cell secretion deficient (AKH-SD), AKH-RNAi, AKH-receptor mutant (GRHR mutant) as well as flies overexpressing AKH using the Gal4/UAS system. AKH is the insect counterpart of glucagon in mammals, and as such, this research has possible implications to molecular signaling pathways by glucagon in humans.