there was a significant negative correlation between weight-adjusted antipyrine clearance and the urinary excretion of the porphyrin precursors , delta-aminolaevulinic acid ( r = 0.86 , p less than 0.001 ) and porphobilinogen ( r = 0.82 , p less than 0.002 ) .
C2917401
porphyrin
C0002563
delta-aminolaevulinic acid