Control of the insect metamorphic transition by ecdysteroid production and secretion

Ecdysteroids are a class of steroid hormones that controls molting and metamorphic transitions in Ecdysozoan species including insects, in which ecdysteroid biosynthesis and its regulation have been extensively studied. Insect ecdysteroids are produced from dietary sterols by a series of reduction-oxidation reactions in the prothoracic gland and in Drosophila they are released into the hemolymph via vesicle-mediated secretion at the time of metamorphosis. To initiate precisely controlled ecdysteroid pulses, the prothoracic gland functions as a central node integrating both intrinsic and extrinsic signals to control ecdysteroid biosynthesis and secretion. In this review, we outline recent progress in the characterization of ecdysone biosynthesis and steroid trafficking pathways and the discoveries of novel factors regulating prothoracic gland function.

Automated summary

Ecdysteroids, a type of steroid hormones, regulate molting and metamorphosis in insects, being produced in the prothoracic gland through reduction-oxidation reactions from dietary sterols. The prothoracic gland acts as a central node integrating signals to control ecdysteroid biosynthesis and secretion, ensuring precise pulses of these hormones during metamorphosis. Recent research has focused on characterizing ecdysone biosynthesis, steroid trafficking pathways, and identifying new factors that regulate prothoracic gland function.