PHEROMONOTROPIC ACTIVITY OF NATURALLY-OCCURRING PYROKININ INSECT NEUROPEPTIDES (FXPRLAMIDE) IN HELICOVERPA-ZEA

Insect neuropeptides, having the common C-terminal sequence FXPRLamide (X = V, T, S, or G), were rested for pheromonotropic activity in the moth, Helicoverpa tea. Dose-response studies indicated that locustamyo tropin-II or locustapyrokinin-II induced production of more pheromone than was stimulated by the pheromone biosynthesis activating neuropept ide of this moth. Other peptides showed various degrees of pheromonotr opic activity. The data indicated that substitution of the variable am ino acid in the C-terminal pentapeptide sequence resulted in significa nt differences in pheromonotropic activity. However, the overall struc ture of the peptide was also found to be of importance.