The corpora cardiaca (CC) of the pneumorid grasshopper species Bullacris discolor contain at least one substance that causes hyperlipaemia in the migratory locust. Isolation of neuropeptides belonging to the adipokinetic hormone (AKH) family was achieved by single-step reversed-phase high performance liquid chromatography (RP-HPLC) of CC extracts and monitoring tryptophan fluorescence. The material of the bladder grasshopper showed three distinct fluorescence peaks with adipokinetic activity in the migratory locust. The peptide sequences were identified by Edman degradation after the N-terminal pyroglutamate residue had been cleaved off enzymatically, and the exact peptide masses were determined by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. Moreover, the assigned peptides were synthesised and natural and synthetic peptides were compared in their behaviour in RP-HPLC. B. discolor stores three AKH peptides in its CC: two of those are octapeptides, Schgr-AKH-II (pELNFSTGWamide) and Peram-CAH-II (pELTFTPNWamide), whereas the third peptide is a decapeptide, Phyle-CC (pELTFTPNWGSamide. The concentration of carbohydrates in the haemolymph of B. discolor is about 3 times higher than the lipid concentration. Upon injection with synthetic Schgr-AKH-II no adipokinetic or hypertrehalosaemic effect was measurable. A literature survey appears to indicate that an active role of these AKH peptides in substrate mobilisation is only overtly displayed in those caeliferan species that undertake well-defined flight periods.
The corpora cardiaca (CC) of the two grasshopper species Zonocerus elegans (Pyrgomorphidae) and Lamarckiana sparrmani (Pamphagidae) contain (a) substance(s) that cause(s) hyperlipaemia in the migratory locust and hypertrehalosaemia in the American cockroach. Isolation of neuropeptides belonging to the adipokinetic hormone (AKH) family was achieved by single-step reversed-phase high performance liquid chromatography of CC extracts from both species and monitoring tryptophan fluorescence. The material of both species showed three distinct fluorescence peaks with adipokinetic activity in the migratory locust. The peptides were identifid by at least two of the following methods: (1) sequencing by Edman degradation, (2) sequencing by tandem fast atom bombardment mass spectrometry, (3) mass determination by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry and (4) co-elution of the native and synthetic peptides. Both species were found to have three AKH peptides stored in the CC, but unlike in other grasshoppers, none of those peptides were decapeptides. In Z. elegans the following three octapeptides occur: Schgr-AKH-II (pELNFSTGWamide), Peram-CAH-II (pELTFTPNWamide) and Phymo-AKH-III (pEINFTPWWamide), whereas L. sparrmani contains the octapeptides Grybi-AKH (pEVNFSTGWamide), Pyrap-AKH (pELNFTPNWamide) and also Phymo-AKH-III. Conspecific bioassays show no adipokinetic and only a weak (not significant) hypertrehalosaemic effect (in the pamphagid grasshopper). Some explanations are offered on the possible role of these peptides in the species investigated by interpreting their life style.