Some Aspects of the Biosynthesis of the Molting Hormones in Calliphora

The early finding by Karlson and Hoffmeister (1963) that exogenous cholesterol can be utilized in vivo for the synthesis of molting hormone (MH) in Calliphora erythrocephala appeared to pave the way for the analysis of the biosynthetic pathway involved, but relatively little progress in establishing the early steps seems to have been made so far. We are concerned here to review briefly the following questions relating to MH synthesis: 1 Which hormonally active compounds are produced in Calliphora, and when? 2 Is the synthesis of intermediate storage precursors indicated? 3 Where does the synthesis of MH occur?