Characteristics of a neurohormone that controls sex pheromone production in Heliothis zea

Abstract

A neuropeptide hormone that controls production of the sex pheromone in Heliothis zea females, originates in the sub-oesophageal ganglion. Because of the difficulty in separating brain from sub-oesophageal ganglion, the entire complex was used in all the experiments unless otherwise stated. Pheromonotropic activity was maximal in brain + sub-oesophageal ganglion extracts from 1–2-day old adults. This age corresponds to normal peak pheromone production in the females. The hormone caused significant pheromonotropic activity within 15 min after injection of the brain + sub-oesophageal ganglion homogenate into ligated females, and reached the peak in 4 h. Activity was detected with a crude preparation of the hormone at 1 8th brain + sub-oesophageal ganglion equivalent. High-performance size-exclusion chromatography of the extracts of brain + sub-oesophageal ganglion indicated that the pheromone-biosynthesis activating neuropeptide may occur in more than one active form. The hormonal activity was destroyed by carboxypeptidase Y and TPCK trypsin, but activity was not destroyed by treatment with aminopeptidase M. These results indicate that the hormonal substance is proteinaceous and may have a blocked NH 2-terminus. Occurrence of pheromonotropic activity in brain + sub-oesophageal ganglion homogenates from other moth species and a species of cockroach indicates the wide distribution of hormones with similar activity.