Activation of fat body in Periplaneta americana (Blattoptera: Blattidae) by hypertrehalosemic hormones (HTH): new insights into the mechanism of cell signalling

摘要

In cockroaches and certain other insects, the concentration of trehalose in the haemolymph is increased by hypertrehalosaemic hormone (HTH), a neuropeptide originating in the corpus cardiacum. A vital step in the action of HTH to promote conversionof glycogen stored in the fat body to trehalose is the activation of phosphorylase. The means by which HTH activates phosphorylase, with particular emphasis on its role in the regulation of intracellular calcium, is discussed. Additional information supporting the view that HTH-stimulated synthesis of trehalose, and possibly its release from the trophocyte, is regulated by fatty acids and eicosanoids is presented.