The relative potencies of two known locust adipokinetic hormones

Abstract

Natural adipokinetic peptides I and II have been isolated from corpora cardiaca of Locusta, and their effects on hyperlipaemia, fat body phosphorylase activation, and lipoprotein-A + formation investigated. At saturation doses for each of these assays, adipokinetic hormone I is more effective than hormone II. In these systems, however, adipokinetic hormone II is unable to induce, even at high doses, the magnitude of response elicited by hormone I. When assayed for their hyperlipaemic effects, two adipokinetic peptides from the corpora cardiaca of Schistocerca also have similar differential potency to those in Locusta. Interestingly, although adipokinetic hormone I from Locusta is more potent in eliciting the above responses, adipokinetic hormone II is more effective than hormone I in bringing about an accumulation of cAMP in the fat body.