An automated technique for the analysis of plasma guanidino acids, and some findings in chronic renal disease.

A sensitive method for the quantitative determination of all guanidino compounds in human serum, including basic compounds such as methylguanidine, was developed by the adaptation of the Technicon automatic amino acid analyzer. Elution buffers with very high pH and molarity are employed for the elution of very basic compounds from the column. Automatic quantitative determination of the plasma guanidino compounds was performed with biacetyl alpha-naphthol, a specific reagent for the guanidino group. This method permitted the quantitative automatic determination of guanidino compounds in less than 1 ml of serum of normal or uremic patients. Guanidino propionic acid and guanidino succinic acid were identified in high concentrations in uremic sera. Methyl guanidine, and guanidine were in smaller concentrations. Guanidino acetic acid and guanidino butyric acid were present in normal plasma in quantities not significantly different from those in uremic plasma.