Locust corpora cardiaca contain an inactive adipokinetic hormone

Abstract

A neuropeptide from the migratory locust, Locusta migratoria, has been identified as a novel member of the family of adipokinetic hormones (AKHs). The peptide is probably synthesised in the brain because it is the first AKH found in the storage lobe, whilst the three`classic' Locusta AKHs are present in the glandular lobe of the corpora cardiaca. In locusts, the peptide has no biological activity usually associated with AKHs. There is only 36^56% sequence identity with the three LomAKHs, but 78% identity with the Drosophila melanogaster AKH, Drm-HrTH. The new peptide is active in the American cockroach, Periplaneta americana, and was provisionally named L. migratoria hypertrehalosaemic hormone', Lom-HrTH; its biological role in locusts remains to be established. The high degree of identity with Drm-HrTH suggests that Lom-HrTH is an ancient molecule.z 1999 Federation of European Biochemical Societies.

Peptidomic survey of the locust neuroendocrine system

“…This peptide was also found to be identical in S. gregaria (Siegert, 1999). We here provide evidence that this peptide is (among others) produced by the pars intercerebralis.…”

“…The mass of HrTH was also observed in the corpora cardiaca, the stomatogastric nervous system, proto-and tritocerebrum and the thoracic ganglia. In cockroaches, HrTH increases hemolymph trehalose levels (Siegert, 1999). Its biological role in locusts remains to be established.…”

Identification and Functional Characterization of Two Orphan G-protein-coupled Receptors for Adipokinetic Hormones from Silkworm Bombyx mori

“…All pictures and data shown are representative of at least three independent experiments. migratoria (29,30). In Lepidoptera, the first AKH peptide was identified from the tobacco hornworm, Manduca sexta (9).…”

Regulation of carbohydrate metabolism and flight performance by a hypertrehalosaemic hormone in the mosquito Anopheles gambiae

“…Anoga-AKH-I stimulated a hyperlipaemic response in Locusta (Table 3). Anoga-AKH-II was tested because it shares 80% similarity with the fourth Locusta AKH (Locmi-HrTH), which showed hypertrehalosaemic activity in P. americana (Siegert, 1999), and in the assay with this species, the mosquito AKH decapeptide was inactive (Table 4).…”

“…This and the lack of a Gly (G) at position 9 that is typical for larger AKHs (Gäde et al, 1997), might be the reason why no detectable metabolic effect was seen. The locust peptide induced a weak hypertrehalosaemic effect in the cockroach and was named Locmi-HrTH (P. americana; Siegert, 1999), but Anoga-AKH-II had no such activity in the same cockroach (Table 4). Since it has been speculated that both of these decapeptides are synthesised in the brain and not the corpora cardiaca, they are most probably not typical AKHs (Siegert, 1999;Kaufmann and Brown, 2006), and their function remains unknown.…”