Detection and quantification of 5-hydroxyoxindole in mammalian sera and tissues by high performance liquid chromatography with multi-electrode electrochemical detection.

5-hydroxyoxindole is an endogenous tryptophan metabolite present in circulating blood and in some tissues at the nmol level, its determination using HPLC-ECD will be useful for elucidating the role of this molecule in normal and disease conditions.