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Ecdysteroids from developing eggs of Pieris brassicae
Author(s) -
Beydon Philippe,
Permana Agusdana,
Colardeau Jacqueline,
Morinière Madeleine,
Lafont René
Publication year - 1989
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.940110102
Subject(s) - ecdysone , pieris brassicae , biology , ecdysteroid , 20 hydroxyecdysone , hatching , instar , metabolism , larva , botany , medicine , endocrinology , biochemistry , zoology
Ecdysone metabolism in Pieris brassicae eggs was revealed after injection of [ 3 H]ecdysone into eggs. Labeled ecdysteroids were analyzed by HPLC. The metabolic fate of [ 3 H]ecdysone is similar to that observed during postembryonic development, i.e., the larval instars and pupal instar. The ecdysone molecule is affected by hydroxylations at C‐20 and at C‐26; 26‐hydroxyecdysteroids can be further oxidized into ecdysteroid acids. In an effort to identify egg ecdysteroids, we examined the metabolism of [ 3 H]cholesterol injected into female pharate adults to achieve long‐term labeling. In eggs, [ 3 H]cholesterol was converted to 20‐hydroxyecdysonoic acid, ecdysonoic acid, 20‐hydroxyecdysone, and ecdysone. The rates of [ 3 H]cholesterol incorporation into ecdysteroids increase according to the age of the eggs (from 0.06% at laying to 0.12% at hatching), while the cholesterol level remains constant throughout embryogenesis, suggesting that the embryos of Pieris brassicae can produce ecdysteroids either from cholesterol or from apolar ecdysteroids not identified by the analytical method. Pieris eggs contain amounts of ecdysteroids which increase from 1.5 nmol/g at laying to 3.8 nmol/g at hatching.