ISSN:
1432-136X
Keywords:
Adipokinetic hormone
;
Fatty acid synthesis
;
Lipid mobilization
;
structure/activity
;
Locusta migratoria
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract Locusta migratoria has three adipokinetic hormones, adipokinetic hormone-I, II and III. Adipokinetic hormone-III (〈QLNFTPWWa) is surprisingly potent (EC50=1.33·10-10 mol·l-1) compared with other adipokinetic hormones (EC50≥5.33·10-10 mol·l-1) at inhibiting acetate uptake into locust fat body in vitro, especially so when it is only moderately potent in mobilizing lipid in vivo. The Trp7 in adipokinetic hormones-III, alongside the Trp8 characteristic of adipokinetic hormones, is not seen in any other adipokinetic hormones. To test whether this is responsible for the high potency of adipokinetic hormone-III in the assay in vitro, novel peptides were synthesised to include or remove this structural motif. Thus, 〈QLNFTPWWGTa (Trp7-Locusta-adipokinetic hormone-I or [Gly8a-Thr8b]-Locustra-adipokinetic hormone-III); 〈QLNFTPNWa (des[Gly9-Thr10]-Locusta-adipokinetic hormone-I or Asn7-Locusta-adipokinetic hormone-III); 〈QLNFSAWWa (Trp7-Locusta-adipokinetic hormone-II) and 〈QVNFSTWWa (Trp7-Acheta-adipokinetic hormones) were tested both in vitro and in vivo. Except for Trp7-adipokinetic hormone-I in the acetate uptake assay, each of these analogues is less potent then its respective parent, irrespective of the assay. However, the acetate uptake response is highly tolerant of peptides containing Trp7-Trp8, whereas this motif markedly reduces potency in the lipid assay. The different responses exploited in these assays may be exerted through different receptor populations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00264640
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