PRELIMINARY ASSESSMENT OF GLYCINE CONJUGATION OF PARA-AMINOBENZOIC ACID AS A QUANTITATIVE TEST OF LIVER-FUNCTION

Objectives: Our hypothesis is that because of its hepatic metabolism p araaminobenzoic acid (PABA) could be a test of liver function. Design and methods: PABA is well absorbed by the gastrointestinal tract and a cetylated and conjugated in the liver to glycine before being excreted . Its three major metabolites include para-acetoamidobenzoic acid (PAA BA), paraaminohippuric acid (PAHA), and paraacetamidohippuric acid (PA AHA). In this study, we measured the metabolism of lidocaine to monoet hylglycine-xylidide (MEGX) and PABA to PAHA + PAAHA/PABA + PAABA + PAH A + PAAHA (hippurate ratio) in 14 patients with liver disease and 12 c ontrol subjects. Results: Comparison of the total bilirubin with the h ippurate ratio (at 30 min) and the conventional MEGX test (at 15 min) was assessed. The 30 min hippurate ratio correlated well with the 15 m in MEGX results (r = 0.69). Conclusions: While these results are preli minary the PABA test appears to be equally sensitive to MEGX and has t he distinct advantage over the MEGX test of being administered orally versus the intravenous administration of lidocaine which is often asso ciated with unwanted side-effects such as hypotension, drowsiness and paresthesias.