Constituents of human meconium: II. Identification of steroidal acids with 21 and 22 carbon atoms.

Monohydroxylated acid fraction isolated from human meconium was found to contain, in addition to C20 and C24 acids identified previously, three C22 bile acids-(20S)-3 alpha-hydroxy-23,24-bisnor-5 beta-cholan-22-oic, (20S)- and (20R)-3 beta-hydroxy-23,24-bisnor-chol-5-en-22-oic, and one C21 acid-3 beta-hydroxypregn-5-en-21-oic. These compounds were identified by capillary gas chromatography-mass spectrometry and by comparison with standards. It is postulated that these C22 acids, as well as the two monohydroxylated C24 bile acids (lithocholic and 3 beta-hydroxychol-5-enoic) are produced in the maternal intestine by microbial flora and transferred to the fetus through the placenta.