Metabolism of 3β-Hydroxy-5β-(3α-3H)-cholest-7-en-6-one in Calliphora stygia

Abstract 3β- Hydroxy -β-(3α- 3 H )- cholest -7- en -6- one (1) is metabolised in Calliphora stygia at the time of puparium formation to ( 3α- 3 H )-β- ecdysone (2) in about the same yield (0.02%) as (1α- 3 H)-cholesterol. However, the ketone (1) may not be a natural precursor of ecdysones in this insect. 2β,3β- Dihydroxy -5β-(3α- 3 H )- cholest -7- en -6- one (3) was identified in the metabolites but 3β,14α- dihydroxy -5β-(3α- 3 H )- cholest -7- en -6- one (4) was not confirmed as a metabolite.