Steroids in the Feces of a Marine Bivalve

Abstract

The present study deals with the steroids in the feces of short-necked clams, Tapes japonica. The fecal sterols had a composition similar to the muscle sterols of the clam. The keto-steroid fraction showed seven components on gas-liquid chromatography, and a Δ⁴-3-keto-steroid structure was indicated by ultraviolet and infrared absorption spectra. The components of the keto-steroids were identified by gas-liquid chromatography and mass spectrometry as 24-norcholesta-4, 22-dien-3-one (4.4%), cholesta-4, 22-dien-3-one (1.7%), cholest-4-3n-3-one (53%), 24-methylcholesta-4, 22-dien-3-one (5.8%), 24-methylenecholst-4-en-3-one (19.0%), 24-ethylcholest-4-en-3-one (14.7%) and 24-ethylidenecholest-4-en-3-one (0.9%).
It is suggested that the fecal keto-steroids of the clam are microbial transformation products of sterols in their digestive tracts.