From the viewpoint of comparative biochemistry, the sterol compositions of mollusks belonging to the class Gastropoda (three orders, nine families, sixteen genera, seventeen species), Pelecypoda (two orders, three families, three genera, three species), and Polyplacophora (one species) were investigated by using gas-liquid chromatography on 1.5% OV-17.
The gastropods were found to contain cholesterol as a main sterol. In the case of Murex asianus, Cymatiidae sp., Charonia sauliae, and Conomurex luhuanus, however, other C_27- and C_28- sterols were detected in addition to cholesterol (42-64%). Compared to the gastropods, the pelecypods appeared to contain relatively small amount of cholesterol (26-35%) and revealed the very complex composition of sterols. On the other hand, the chiton, Liolophura japonica, belonging to the most primitive mollusks, was found to contain 7-cholestenol ( ?? ⁷-sterol) contrasting that of the other mollusks.