Tubular sites of action of heavy metals, and the nature of their inhibition of amino acid reabsorption

Functional lesions after exposure to heavy metals are reviewed in relation to renal amino acid transport. Such effects may vary from metal to metal but they do not appear to represent general cytotoxicity. In agreement with the conclusion that the rate- and specificity-determining step in amino acid reabsorption is located at the brush border, metals exert their primary effect at that site. The inhibition kinetics resemble those seen with uncompetitive inhibitors but the precise nature of the interaction between metals and carriers remains to be clarified. Peritubular transport of dicarboxylic amino acids is also sensitive to metals, but this action does not influence reabsorption of these acids.