Ecdysis-triggering hormone

EH was initially identified as a circulating neuropeptide that was thought to act back on the CNS to trigger ecdysis behaviors. In pharate adult Manduca sexta. large amounts of EH accumulate in the CC-CA complex prior to ecdysis and are released into the hemolymph late in the molt. A set of laterd brain neurosecretory cells (NSCs) that projected to the CC-CA were found to contain EH-like activity CLL). It was clear, however, that these cells were not responsible for EH release in larvae or pupae since in these stages release of the hormone comes from the ventral nervous system Q). The recent discovery of the cells responsible for this release has prompted a re-evaluation of the route by which EH triggers ecdysis. 

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