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 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.
Candy
D J
DJ
School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK. D.J.Candy@bham.ac.uk
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004075:Diglycerides / Q000032:analysis; D006110:Grasshoppers / Q000737:chemistry / Q000502:physiology*; D006458:Hemolymph / Q000737:chemistry*; D007301:Insect Hormones / Q000032:analysis* / Q000302:isolation & purification; D011863:Radioimmunoassay
D004075:Diglycerides; D007301:Insect Hormones; C014956:adipokinetic hormone (locust)