Early stages of ecdysteroid biosynthesis: The role of 7-dehydrocholesterol

摘要: Abstract The synthesis of [4- 14 C]cholesta-4,6-dien-3-one and C]3β-hydroxy-5α-cholestan-6-one is described. Both C]cholest-4-en-3-one were not incorporated significantly into ecdysteroids compared to [1α,2α- 3 H]cholesterol in fifth instar maturing adult female Schistocerca gregaria . Similarly, was the latter system. results suggest that none three C-substrates are intermediates ecdysteroid biosynthesis from cholesterol, although possible complications permeability barriers cannot be discounted. C, 7- H]7-dehydrocholesterol has been synthesized Spodoptera littoralis pupae. Although approximately half tritium eliminated during S. , there essentially complete retention support direct incorporation 7-dehydrocholesterol via cholesterol. A explanation for loss appreciable discussed.