Journal of Lipid Research, Vol 22, 474-484, Copyright © 1981 by Lipid Research, Inc.
Thin-layer and gas--liquid chromatographic identification of neutral steroids in human and rat feces
DJ McNamara, A Proia and TA Miettinen
Natural steroids from rat and human feces were fractionated by sequential
thin-layer chromatography (TLC) on Florisil, silica gel, and silver
nitrate-impregnated silica gel and analyzed by gas--liquid chromatography
(GLC). Cholesterol, coprostanol, and coprostanone accounted for more than
95% of the endogenous neutral steroid in human feces, the remainder being
predominantly cholestanol. In addition, evidence was obtained for the
presence in human feces of trace amounts of epicoprostanol and
cholestanone. In rat feces, several cholesterol precursors that probably
originated in the skin (and were ingested during fur=licking) were detected
in relatively large amounts, accounting for as much as 27% of the total
fecal neutral steroids, whereas these steroids were quantitatively trivial
in human feces. As with cholesterol, the major dietary plant sterols
(sitosterol, campesterol, and stigmasterol) were converted by intestinal
bacteria to the corresponding coprostane and ketonic derivatives during
intestinal transit in both human beings and rats. This combined use of TLC
and GLC provided for the separation of steroids of endogenous and dietary
origin that could not be resolved by either system alone. A majority of the
fecal steroids could be tentatively identified by their chromatographic
behavior in different TCL systems and on GLC, even when reference standards
were unavailable.