Ecdysteroid Metabolism In The Terrestrial Snail Cepaea-Nemoralis (L)

Summary Garden snails (Cepaea nemoralis) contain both ecdysone and ecdysterone. Attempts to determine whether they originate from their food or are endogenously synthesized did not allow a definite conclusion. The metabolism of ecdysone and 20-hydroxyecdysone in Cepaea nemoralis has been investigated by using tritiated hormone injections followed by HPLC analysis of labelled compounds. It was observed that snails convert ecdysone into 20-hy-hroxyecdysone and the latter into two new ecdysteroids. These metabolites were isolated and identified by mass spectrometry and two-dimensional PMR. They correspond to 20-hydroxyecdysone 22-acetate and 16β,20-dihydroxyecdysone. We propose the name of ‘malacosterone’ for the second compound. Snails do not form ecdysonoic acids nor polar conjugates. These pathways are common to other gastropod species tested and they are discussed by comparison with those already described in Arthropods.