Abstract
Two distinct diuretic peptides affect the rate of fluid secretion of the Malpighian tubules in Locusta. Diuretic peptide (DP 1) has a molecular mass ca. 4500 and acts via cyclic AMP: the second diuretic peptide (DP 2) has a molecular mass of ca. 1000 and operates via an unknown transduction mechanism: the possible involvement of cGMP. calcium mobilization and the breakdown of phosphoinositides has been investigated. Preliminary sequence data for DP 1 is reported and details are provided concerning the isolation and characterisation of a peptide which is present in large amounts in the storage lobes of the corpora cardiaca and co-chromatographs with DP 1 on high performance size-exclusion chromatography. Adipokinetic hormones (AKH) present in the corpora cardiaca of insects can regulate lipid metabolism. AKH occurs in two forms as AKH I and as AKH II: these hormones have been isolated and characterised in both Locusta and Schistocerca. AKH I is a decapeptide of the following structure: pGlu-Leu-Asn-Phe-Thr-Pro-Asn-Trp-Gly-ThrNH2 and is identical in Locusta and Schistocerca. AKH II is different in these two insects: AKH II-L from Locusta is: pGlu-Leu-Asn-Phe-Ser-Ala-Gly-TrpNH2 and AKH II-S from Schistocerca is: pGlu-Leu-Asn-Phe-Ser-Thr-Gly-TrpNH2. These structures have been established using newly developed quick and simple procedures employing HPLC and gas-phase sequencing which enables full structures to be elucidated from 2-3 nmoles of peptide. Comparisons are made between the structures of AKH and related peptides isolated from insects and crustacea.
Original language | English |
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Pages (from-to) | 407-410 |
Number of pages | 4 |
Journal | Peptides |
Volume | 6 |
Issue number | SUPPL. 3 |
DOIs | |
Publication status | Published - 1 Jan 1985 |
Keywords
- Adipokinetic hormones
- Diuretic peptides
- Gas-phase sequencing
- HPLC
- Insects