Preliminary assessment of glycine conjugation of para-aminobenzoic acid as a quantitative test of liver function.
OBJECTIVE
Our hypothesis is that because of its hepatic metabolism paraaminobenzoic acid (PABA) could be a test of liver function.


METHODS
PABA is well absorbed by the gastrointestinal tract and acetylated and conjugated in the liver to glycine before being excreted. Its three major metabolites include para-acetoamidobenzoic acid (PAABA), paraaminohippuric acid (PAHA), and paraacetamidohippuric acid (PAAHA). In this study, we measured the metabolism of lidocaine to monoethylglycinexylidide (MEGX) and PABA to PAHA+PAAHA/PABA+PAABA+PAHA+PAAHA (hippurate ratio) in 14 patients with liver disease and 12 control subjects.


RESULTS
Comparison of the total bilirubin with the hippurate ratio (at 30 min) and the conventional MEGX test (at 15 min) was assessed. The 30 min hippurate ratio correlated well with the 15 min MEGX results (r = 0.69).


CONCLUSIONS
While these results are preliminary the PABA test appears to be equally sensitive to MEGX and has the distinct advantage over the MEGX test of being administered orally versus the intravenous administration of lidocaine which is often associated with unwanted side-effects such as hypotension, drowsiness and paresthesias.
Duffy
L F
LF
Department of Pediatrics, George Washington University School of Medicine, Washington, DC, USA.
Kerzner
B
B
Seeff
L
L
Barr
S B
SB
Soldin
S J
SJ
D010129:4-Aminobenzoic Acid / Q000378:metabolism*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000410:Alanine Transaminase / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D001663:Bilirubin / Q000097:blood; D002648:Child; D002675:Child, Preschool; D005260:Female; D005998:Glycine / Q000378:metabolism*; D006626:Hippurates / Q000097:blood; D006801:Humans; D008012:Lidocaine / Q000031:analogs & derivatives / Q000378:metabolism; D008107:Liver Diseases / Q000145:classification / Q000175:diagnosis*; D008111:Liver Function Tests / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011517:Prothrombin Time
D006626:Hippurates; D008012:Lidocaine; C001173:monoethylglycinexylidide; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D001663:Bilirubin; C030514:hippuric acid; D005998:Glycine; D010129:4-Aminobenzoic Acid