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Adipokinetic hormone of the true armyworm, Pseudaletia unipuncta: immunohistochemistry, amino acid analysis, quantification and bioassay
Author(s) -
ORCHARD IAN,
CUSSON MICHEL,
McNEIL JEREMY N.
Publication year - 1991
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/j.1365-3032.1991.tb00583.x
Subject(s) - adipokinetic hormone , manduca sexta , biology , hemolymph , sphingidae , endocrinology , medicine , bioassay , manduca , botany , biochemistry , insect , neuropeptide , receptor , ecology
A cluster of five to seven AKH‐like immunoreactive cells lie in each lobe of the paired corpora cardiaca of the true armyworm, Pseudaletia unipuncta. These cells form a mesh work of immunoreactive processes within the corpora cardiaca, and immunoreactive tracts projecting posteriorly over the aorta. Reversed‐phase high performance liquid chromatography of extracts of the corpora cardiaca of P.unipuncta revealed a single large U.V. absorbent peak with a retention time identical to synthetic Manduca‐ AKH. Amino acid analysis of the contents of this peak yielded a composition identical to that of synthetic Manduca‐AKH which was analysed in a parallel manner. Furthermore the material within the peak possessed adipokinetic activity when bioassayed in day 2 adult male P. unipuncta. The corpora cardiaca of similar individuals were found to contain approximately 17.6ng (17.6pmol) of Manduca‐AKH equivalents per pair. Injection of Manduca‐AKH into 2‐day‐old adult male P.unipuncta resulted in a dose‐dependent elevation in haemolymph lipid levels with a maximum level of 80–90μmg/μl obtained with 5–10 ng of Manduca‐AKH. Continuous flight also elevated haemolymph lipid levels in day 4 adult males with a significant elevation evident in the first samples taken after 15 min of flight and lipid levels plateauing at approximately 100 μg/μl by about 60 min of flight.