THE RESISTANCE OF SOME o-AMINOARYL SULPHATES TO HYDROLYSIS BY ARYL

Aromatic amines are oxidized in animal tissues to oand p-aminophenols, which are rapidly conjugated to give either sulphates or glucosiduronates. Some of the carcinogenic aromatic amines appear to produce their biological effects after conversion into o-aminophenols. 2-Naphthylamine, for example, which produces bladder cancer, is oxidized to 2-amino-6-naphthol and 2-amino-inaphthol by liver slices, but these. products are rapidly conjugated to yield sulphates and glucosiduronates in liver tissue (Booth, Boyland & Manson, 1955). Whereas 2-amino-6-naphthyl sulphate was hydrolysed by rat kidney, 2-amino-inaphthyl sulphate was not hydrolysed by any of the tissues which were examined. One would expect that the conjugated forms of aminophenols excreted in urine would be hydrolysed by the glucuronidase and sulphatase which are present in almost all urines (Boyland, Wallace & Williams, 1955). The glucosiduronates of both 2-amino-6naphthol and 2-amino-1-naphthol, and 2-amino-6naphthyl sulphate are hydrolysed enzymically, but 2-amino-1-naphthyl sulphate is hydrolysed neither by urinary nor by any other sulphatases. Some other o-aminoaryl sulphates are resistant to hydrolysis by sulphatase, but all other aryl sulphates which have been examined are hydrolysed by aryl sulphatases. The aminophenyl sulphates derived from carcinogenic aromatic amines are generally resistant to the hydrolytic action of sulphatases. Although 2-naphthylamine is carcinogenic when given to dogs, it is not active when implanted in the mouse bladder under conditions in which 2amino-l-naphthol induces bladder cancer (Bonser, Clayson, Jull & Pyrah, 1952). When tested under the same conditions 2-amino-1-naphthyl sulphate did not induce bladder cancer (Bonser, Clayson & Jull, 1954). METHODS