The orientation of the hydroxyl group at the 7-position defines whether they are α- or β-muricholic acid.
Muricholic acids are detectable at low concentrations in human urine.
[3] In conventional mice with a normal microbiome, ω-muricholic acid (with hydroxyls in the 6α- and 7β-positions), and various sulfated forms are also found.
Conjugation with taurine (to give tauromuricholic acids which are the main forms), or with glycine (to give glycomuricholic acids) takes place in the liver before secretion.
[citation needed] The enzyme responsible for the 6-hydroxylation reactions forming muricholates in mice is the cytochrome P450 Cyp2c70.