Molting hormone
- Pronunciation
- /MOHLT-ing HOR-mohn/
- Category
- Physiology
- Singular
- molting hormone
- Plural
- molting hormones
Definition
Any steroid that triggers and coordinates the molting process () in . In insects and most crustaceans, the primary active molting hormone is 20-hydroxyecdysone, synthesized from the prohormone secreted by the prothoracic glands or equivalent structures. regulate the shedding of the old , epidermal proliferation, and the behavioral sequence of ecdysis itself. They also influence , developmental transitions, and in some , reproductive or .
Etymology
From English (to shed an outer covering) + (Greek hormon, setting in motion).
Example
In Manduca sexta (), a pulse of molting initiates the wandering of fifth-instar larvae, followed by , the synthesis of a new , and ultimately to the pupal stage.
Synonyms
- ecdysteroid
- ecdysone (loose, often refers to precursor)
- 20-hydroxyecdysone (specific active form)
Related Terms
- Ecdysis
- apolysis
- ecdysteroid
- Juvenile hormone
- prothoracic gland
- ecdysone receptor
- Cuticle
- Metamorphosis
Usage Notes
distinguish between the prohormone (secreted by glands) and the active molting 20-hydroxyecdysone (produced by peripheral hydroxylation). In casual usage, "ecdysone" is often used loosely for the hormonal system. Crustaceans use similar but with different glandular sources (Y-organs). The term excludes , which modulates type rather than triggering .