A new method for the rapid quantification of 3-oxo-bile acids has been developed. From 5 to 120 μg of oxo-acid in aqueous or ethanolic media are reduced with sodium borohydride. The resulting 3α- and 3β-hydroxy acids are then oxidized in a reaction catalyzed by 3-hydroxysteroid dehydrogenase, during which nicotinamide adenine dinucleotide (NAD) is reduced to NADH. The absorbance of the reaction mixture is determined at 340 nm and is directly proportional to the amount of 3-oxo-acid in the original sample. The method is fully compatible with that used in determining 3α-hydroxy-bile acids.
Beher, W. T.; Lin, G. J.; Sanfield, J.; and Stradnieks, S.
"The Quantitative Determination of 3-oxo-Bile Acids,"
Henry Ford Hospital Medical Journal
: Vol. 26
Available at: https://scholarlycommons.henryford.com/hfhmedjournal/vol26/iss1/2