THE IDENTITY AND PHYSIOLOGICAL ACTIONS OF AN ADIPOKINETIC HORMONE IN ACHETA-DOMESTICUS

An octapeptide which mobilizes lipid and inhibits the incorporation of [H-3]leucine into haemolymph proteins in both Acheta domesticus and Locusta migratoria has been purified from the corpora cardiaca of Acheta. The primary sequence of this Acheta adipokinetic hormone, determined by pulsed liquid-phase Edman sequencing after enzymatic removal of the N-terminal pyroglutamate is: (pGlu)-Val-Asn-Phe-Ser-Thr-Gly-Trp-NH2. This sequence is identical to that of an octapeptide isolated previously from Gryllus bimaculatus and Romalea microptera. Synthetic material with the assigned structure is biologically active and is chromatographically identical to the natural peptide. In both crickets and locusts, the sensitivity of [H-3]leucine incorporation to inhibition by Acheta adipokinetic hormone (EC50 = 5 x 10(-11) M) is two orders of magnitude greater than that of the adipokinetic response (EC50 = 3 x 10(-9) M). Acheta adipokinetic hormone elicits a full adipokinetic response in both Locusta and in Acheta.