Ecdysone is a
prohormone
A prohormone is a committed precursor of a hormone consisting of peptide hormones synthesized together that has a minimal hormonal effect by itself because of its expression-suppressing structure, often created by protein folding and binding additi ...
of the major insect
molting hormone
20-hydroxyecdysone
20-Hydroxyecdysone (ecdysterone or 20E) is a naturally occurring ecdysteroid hormone which controls the ecdysis (moulting) and metamorphosis of arthropods. It is therefore one of the most common moulting hormones in insects, crabs, etc. It is als ...
, which is secreted from the
prothoracic gland
The prothoracic glands are either of a pair of endocrine glands located in the prothorax of certain insects that regulate molting. They have an ectodermal origin and secrete ecdysteroids, such as ecdysone and 20-hydroxyecdysone
20-Hydroxyecdyson ...
s. It is of
steroidal structure. Insect molting hormones (ecdysone and its homologues) are generally called
ecdysteroid
Ecdysteroids are arthropod steroid hormones that are mainly responsible for molting, development and, to a lesser extent, reproduction; examples of ecdysteroids include ecdysone, ecdysterone, turkesterone and 2-deoxyecdysone. These compounds are ...
s. Ecdysteroids act as moulting hormones of
arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chiti ...
s but also occur in other related
phyla where they can play different roles.
In ''
Drosophila melanogaster
''Drosophila melanogaster'' is a species of fly (the taxonomic order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the " vinegar fly" or "pomace fly". Starting with ...
'', an increase in ecdysone concentration induces the expression of genes coding for proteins that the larva requires, and it causes chromosome puffs (sites of high expression) to form in
polytene chromosomes. Recent findings in the laboratory of
Chris Q. Doe have found a novel role of this
hormone
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are require ...
in regulating temporal
gene transitions within
neural stem cells
Neural stem cells (NSCs) are self-renewing, multipotent cells that firstly generate the radial glial progenitor cells that generate the neurons and glia of the nervous system of all animals during embryonic development. Some neural progenitor ste ...
of the fruit fly.
Ecdysone and other ecdysteroids also appear in many plants mostly as a protection agent (
toxins or
antifeedant
Antifeedants are organic compounds produced by plants to inhibit attack by insects and grazing animals. These chemical compounds are typically classified as secondary metabolites in that they are not essential for the metabolism of the plant, but i ...
s) against
herbivorous
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpar ...
insects. These
phytoecdysteroid Phytoecdysteroids are plant-derived ecdysteroids. Phytoecdysteroids are a class of chemicals that plants synthesize for defense against phytophagous (plant eating) insects. These compounds are mimics of hormones used by arthropods in the molting pr ...
s have been reputed to have
medicinal
Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care practic ...
value and are part of herbal
adaptogen
Adaptogens or adaptogenic substances are used in herbal medicine for the claimed stabilization of physiological processes and promotion of homeostasis.
History
The concept of adaptogens was originally created in 1947 to describe a substance that ...
ic remedies like
Cordyceps, yet an ecdysteroid precursor in plants has been shown to have
cytotoxic properties as well as
antioxidant properties on
lipid peroxidation.
Tebufenozide
Tebufenozide is an insecticide that acts as a molting hormone. It is an agonist of the ecdysone receptor that causes premature molting in larvae. It is primarily used against caterpillar pests.
Because it has high selectivity for the targeted ...
, sold under the
Bayer trademark MIMIC,
apvma.gov.au: "Tebufenozide in the product Mimic 700 WP Insecticide, Mimic 240 SC Insecticide"
/ref> has ecdysteroid activity although its chemical structure has little resemblance to the ecdysteroids.
See also
* Ecdysone receptor
The ecdysone receptor is a nuclear receptor found in arthropods, where it controls development and contributes to other processes such as reproduction. The receptor is a non-covalent heterodimer of two proteins, the EcR protein and ultraspiracle ...
* PTTH - Metamorphosis Initiator hormone
External links
Ecdybase
The Ecdysone Handbook - a free online ecdysteroids database
Notes
Steroids
Insect hormones
Insect developmental biology
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