Eclosion hormones

Bioassays commonly provide the initial means of detecting neuropeptide activity. The factor(s) responsible for this activity are assigned names reflecting the functions detected with the bioassay (e.g., adipoianetic hormone, AKH diuretic hormone, DH eclosion hormone, EH pheromone biosynthesis activating neuropeptide, PBAN prothoracicotropic hormone, PTTH and so forth). As more of these factors are discovered and characterized, not only are biologic ... 

We used the Bombyx adult heads as a source of PTTH (5) along with bombyxins (formerly 4K-PTTH, insulin-related peptides possessing PTTH activity in the brainless pupae of Sarnia cynthia ricini) (6), eclosion hormone (7), melanization and reddish coloration hormone (8) and pheromone biosynthesis activating neuropeptide (9). All these peptide hormones have been isolated and characterized. 

Aliquots from each fraction were desalted and assayed eclosion hormone eluted in the 50 mM NH4OAC fraction, allatotropin in the 100 and 200 mM NH4OAC fractions (JLl), and diuretic hormone in the 400 and 800 mM NH4OAC. 

Eclosion hormone (EH) is a novel insect neurohormone that acts on the nervous system to trigger a stereotyped set of behaviors. The gene that encodes EH was isolated from the moth Manduca sexta and has provided a molecular means to determine the structure of EHs from a variety of insects. Only a few (2-4) neurons in the CNS produce EH and these cells appear to release the peptide both locally within the CNS and systemically into the blood. The former is responsible for causing the behavioral responses while the latter acts on various peripheral targets. 

Eclosion hormone is a unique neuropeptide whose actions are tied to a specific set of behaviors shown at ecdysis. The hormone, in turn, is produced by a gene whose sole product is EH. This gene occurs throughout the insects, and the association of EH with ecdysis behaviors may be an evolutionarily ancient relationship. An intriguing aspect of EH is the small number of neurons that actually express the... 

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