Synthesis and conversion study of a radiolabeled putative ecdysone precursor, 5 beta-cholest-7-ene-3 beta,6 alpha,14 alpha-triol in Locusta migratoria prothoracic glands

In previous studies, we have characterized the last three steps of the biosynthetic pathway of the insect molting hormone, ecdysone. They consist of a series of hydroxylations at the C-25, C-22, and C-2 positions. To explore an early step, we synthesized 5 beta-cholest-7-ene-3 beta,6 alpha,14 alpha-triol in tritiated form. Incubation of this triol with insect prothoracic glands, a well-known site of ecdysone biosynthesis, showed that this molecule can be hydroxylated at the C-25, C-22, and C-2 positions, but neither the triol nor the resulting compounds could be oxidized at the C-6 position to give ecdysone.