Lf. Duffy et al., PRELIMINARY ASSESSMENT OF GLYCINE CONJUGATION OF PARA-AMINOBENZOIC ACID AS A QUANTITATIVE TEST OF LIVER-FUNCTION, Clinical biochemistry, 28(5), 1995, pp. 527-530
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.