Prothoracic gland synthesis of 3-dehydroecdysone and its hemolymph 3β-reductase mediated conversion to ecdysone in representative insects

Abstract

The prothoracic glands of a variety of insects were tested for their ability to synthesize ecdysteroids in vitro. More specifically, they were evaluated for their ability to produce 3-dehydroecdysone and ecdysone using both radioimmunoassay and reverse phase high performance liquid chromatography. Three categories of insect prothoracic glands were noted: a) those producing much more 3-dehydroecdysone than ecdysone; b) glands synthesizing almost equivalent amounts of each of these two ecdysteroids; c) prothoracic glands that yielded more ecdysone than 3-dehydroecdysone. In addition, the 3-oxoecdysteroid 3 beta-reductase activity of the hemolymph of these insects was evaluated for its ability to convert 3-dehydroecdysone to ecdysone. The lepidopteran species tested yielded the most potent enzyme activity, although activity was demonstrated in members of other orders. These data indicate that the dehydroecdysone-ecdysone axis is not restricted to moths and butterflies.

Ecdysone signaling regulates the formation of long-term courtship memory in adult Drosophila melanogaster

“…In Drosophila, steroid hormone synthesis is known to occur primarily in 2 organs, the larval prothoracic gland and the adult female ovary (38)(39)(40)(41)(42). Ecdysteroids are present in adult males as well as females (11).…”

Discrete pulses of molting hormone, 20‐hydroxyecdysone, during late larval development of Drosophila melanogaster: Correlations with changes in gene activity

“…2). The results from the differential screening by H22 (black) and SHO3 (red) anti-ecdysteroid antibodies Gilbert, 1986, 1988;Kiriishi et al, 1990), expressed in pg E equivalents, are graphed versus the HPLC fraction number. Only the initial portion of the chromatogram, up to 60 min elution time employing from 30 to 40% methanol, is shown.…”

“…However, it does not detect the A-ring oxidation, epimerization, or conjugation products of E or 20E such as 3DE or 3D20E, E', or 20E' or their polar phosphate esters . The SHO3 antiserum (a gift of Dr. Sho Sakurai, Kanazawa University) was the result of E-derivatization at the opposite end of the steroid molecule (via the C3 hydroxyl function) to thyroglobulin and so detects mainly E, 20E (E/ 20E cross-reactivity also about 5) and their A-ring oxidized, epimerized, or conjugated metabolites, but not sidechain modified products (Kiriishi et al, 1990). As such, it complements detection by the H22 antibody.…”

Ecdysone Titer Determined by 3DE-3β-Reductase Enhances the Immune Response in the Silkworm

“…In insects, the biosynthesis of the 20E is mainly from the cholesterol pathway in the prothoracic glands (8). Nevertheless, ecdysone can also be directly synthesized from 3-dehydroecdysone (3DE) in other tissues (22)(23)(24). In immature stages of most lepidopteran species, 3DE is the major product of the prothoracic glands.…”