Adipokinetic hormones concentrations in the haemolymph of Schistocerca gregaria, measured by radioimmunoassay
A new procedure for the measurement of adipokinetic hormone (AKH) concentrations in locust ( Schistocerca gregaria) haemolymph is described: Haemolymph is extracted with chloroform/methanol/water and the aqueous layer is fractionated with reverse-phase cartridges and HPLC. The fractions correspondin...
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Veröffentlicht in: | Insect biochemistry and molecular biology 2002-11, Vol.32 (11), p.1361-1367 |
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Sprache: | eng |
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Zusammenfassung: | A new procedure for the measurement of adipokinetic hormone (AKH) concentrations in locust (
Schistocerca gregaria) haemolymph is described: Haemolymph is extracted with chloroform/methanol/water and the aqueous layer is fractionated with reverse-phase cartridges and HPLC. The fractions corresponding to AKH-I (Lom-AKH-I) and AKH-II (Scg-AKH-II) are then measured in a competitive binding assay using specific antibodies and [
3H]AKHs. The procedures could be applied to any peptides containing N-terminal pyroglutamate residues including all members of the adipokinetic/hyperglycaemic/red pigment concentrating hormone family. Results show that the concentrations of both AKH-I and AKH-II increase within 5 min of initiation of flight and are maintained at approx. 15-fold (AKH-I) and 6-fold (AKH-II) the resting levels over flights of at least 60 min. Poisoning of locusts with either the insecticide deltamethrin or with potassium chloride also caused release of hormones. Starvation for 6 h caused elevation of hormone levels in 5th instar nymphs, but starvation for 6 or 20 h had little effect on hormones in adults, despite an increase in haemolymph diacylglycerols at 20 h. |
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ISSN: | 0965-1748 1879-0240 |
DOI: | 10.1016/S0965-1748(02)00056-5 |