Elimination of C-6-hydrogen during the formation of ecdysteroids from cholesterol in Locusta migratoria ovaries.

Being administered to Locusta migratoria adult females, [6-3H, 4-14C]cholesterol was incorporated into ecdysone and 2-deoxyecdysone. The ratio of 3H/14C of the two ecdysteroids isolated from newly laid eggs revealed that C-6-hydrogen of cholesterol was eliminated during the conversion to ecdysteroids in the ovaries of the insects. Thus, a hypothetical mechanism involving migration of the C-6-hydrogen to the C-5 position in the formation of A/B cis junction turned out to be less likely.