Elevated Urinary Excretion of β-Aminoisobutyric Acid and Exposure to Inorganic Lead

Abstract

β-Aminoisobutyric acid (β-AIB), a normal degradation product of thymine, a constituent of DNA and, to a lesser extent, of transfer RNA, is excreted in low levels in human urine. We found that a group of iron workers occupationally exposed to inorganic lead excreted high levels of urinary β-AIB. Elevated urinary excretion of β-AIB was also observed in marmosets, Callithrix jacchus, that received lead acetate in drinking water. Our results suggest that increased urinary excretion of β-AIB could stem from damage to DNA on exposure to lead.