Progesterone metabolism by the echinoderms Asterias rubens and Marthasterias glacialis

The echinoderms Asterias rubens and Marthasterias glacialis metabolize injected [4-(14)C]progesterone to give labelled 3beta-hydroxy-5alpha-pregnan-20-one and 3beta,6alpha-dihydroxy-5alpha-pregnan-20-one. These radioactive products are converted by the animals into conjugated forms that are soluble in aqueous methanol, and which have mobilities on t.l.c. similar to the asterosaponins.