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A new adipokinetic hormone (named Lom-AKH-111) was isolated from the glandular lobes of the corpora cardiaca of Locusta migratoria. At the N-terminus it is blocked by a 5-oxoproline (pyroglutamic acid) residue (< Glu). After enzymatic deblocking, the amino acid sequence of the N-terminus was partly established by automatic Edman degradation to be 1 < Glul-Leu-Asn-Phe-Thr-Pro-. Fast-atom-bombardment spectrometry (FAB-MS) revealed that the new hormone is an octapeptide, which is amidated at the C-terminus, and has a relative molecular mass of 1072. Based on the FAB-MS data the complete sequence is < Glu-Leu-Asn-Phe-ThrPro-Trp-Trp-NH,, which was confirmed by chemical synthesis. All characteristics from HPLC, FAB-MS and biological activity of the natural hormone and the synthetic peptide appeared to be identical. Although the structure of this new hormone resembles that of Lom-AKH-I ( < Glu-Leu-Asn-Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH,), its amino acid sequence points to a completely different route for its biosynthesis, involving a third prohormone. High-[K+]-containing media can cause release of all three adipokinetic hormones in vitro. Interestingly, the new hormone is absent in another locust species, Schistocerca gregaria. Based on in vitro biosynthesis experiments the turnover for this hormone is very high, suggesting an important physiological function. Locusta migratoria is the first insect species in which three different adipokinetic hormones have been demonstrated.The first physiological evidence for the presence of compound(s) with adipokinetic activity in the corpora cardiaca (CC) of the locusts Locusta migratoria and Schistocerca gregaria was reported independently by Beenakkers [l] and by Mayer and Candy 121, respectively. From both species an identical adipokinetic hormone (AKH) was isolated (Lom-AKH-I; for nomenclature see [3]) and sequenced ( < Glu-LeuAsn-Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH,) 141. Both species also contain a second adipokinetic hormone [5] and sequence analysis revealed that this hormone in Locusta (Lom-AKH-11) ( < Glu-Leu-Asn-Phe-Ser-Ala-Gly-Trp-NH,) differs in only one amino acid from that in Schistocerca (Scg-AKH-11) ( < Glu-Leu-Asn-Phe-Ser-Thr-Gly-Trp-NH2) [6].AKHs are synthesized and stored in the glandular lobe of the CC [7 -91 and are colocalized in the same secretory granCorrespondence to R.

Alcohol dehydrogenase (ADH) of Drosophila not only catalyzes the oxidation of ethanol to acetaldehyde, but additionally catalyzes the conversion of this highly toxic product into acetate. This mechanism is demonstrated by using three different methods. After electrophoresis the oxidation of acetaldehyde is shown in an NAD-dependent reaction revealing bands coinciding with the bands likewise produced by a conventional ADH staining procedure. In spectrophotometric measurements acetaldehyde is oxidized in an NADdependent reaction. This activity is effectively inhibited by pyrazole, a specific inhibitor of ADH. By means of gas chromatographic analysis a quick generation of acetate from ethanol could be demonstrated. Our conclusion is further supported by experimental results obtained with either purified ADH F enzyme or genotypes with or without ADH, aldehyde-oxidase, pyridoxal-oxidase and xanthine-dehydrogenase activity. These results are discussed in relation to ethanol tolerance in the living organism in particular with respect to differences found between ADH in Drosophila melanogaster and D. simulans, and in relation to the possible implications for the selective forces acting on ADH-polymorphism.

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