Primary structure of two neuropeptide hormones with adipokinetic and hypotrehalosemic activity isolated from the corpora cardiaca of horse flies (Diptera).

The primary structures of two neuropeptides, Tabanus atratus adipokinetic hormone (Taa-AKH) and Tabanus atratus hypotrehalosemic hormone (Taa-HoTH), from the corpora cardiaca of horse flies (Diptera: Tabanidae) have been determined. Amino acid sequences of Taa-AKH (less than Glu-Leu-Thr-Phe-Thr-Pro-Gly-Trp-NH2) and Taa-HoTH (less than Glu-Leu-Thr-Phe-Thr-Pro-Gly-Trp-Gly-Tyr-NH2) (where less than Glu = pyroglutamic acid) were determined by automated gas-phase Edman degradation of the peptides deblocked by pyroglutamate aminopeptidase and by fast atom bombardment mass spectrometry. The hormones were synthesized, and the natural and synthetic peptides exhibited identical chromatographic, spectroscopic, and biological properties. When assayed in adult face fly males, Taa-AKH and Taa-HoTH demonstrated hyperlipemic activity, in addition, Taa-HoTH also demonstrated a significant hypotrehalosemic activity.