MARINE STEROLS: VI. STEROL BIOSYNTHESIS IN MOLLUSCS AND ECHINODERMS

Abstract
The in vivo incorporation of 2-C14-acetate into digitonin-precipitable material has been demonstrated in two molluscs, mussel (Mytilus californianus) and clam (Saxidomus giganteus). Clams are able to convert 11,14-C14-squalene into digitonin-precipitable material. When the azoylester of the material isolated from clams is chromatographed, the major portion of the radioactivity follows the least polar zone, which has previously been found to contain mainly monounsaturated Δ5-sterols.A starfish (Pisaster ochraceus) has been shown in vivo to convert ingested 4-C14-cholesterol to 7-cholestenol.