Glutathione transferases : markers for renal disease

Glutathione transferases (GST) alpha and pi were purified to homogeneity and used to develop immunochemical methods for analysis of the amount of these proteins in human urine. The methods were employed for diagnosis of renal dysfunctions caused by drugs and industrial chemicals. The distribution of GSTs in human tissues were studied with immunohistochemistry. The alpha form was restricted to a limited number of cell types and tissues, while the pi form was richly represented in most organs. In the kidney the alpha form was found exclusively in the proximal tubules, while the pi form was localized in the distal tubules and the collecting ducts. A radioimmunoassay procedure was developed for quantitation of GST pi. The method was highly specific for GST pi and no cross-reactions were obtained with other proteins. The high stability of GST proteins in urine under various conditions was demonstrated. The two GSTs were followed in the urine of 109 renal transplant recipients in the post-operative period. In the case of cyclosporine A-induced nephrotoxicity the alpha form increased significantly, which was not the case for the pi form. In contrast, acute rejection increased only the excretion of the pi form. An ELISA procedure was developed for GST alpha and pi, which exhibited high sensitivity and specificity. Conditions were established to attain full recovery of the proteins investigated by preventing their adsorption to plastic materials. The composition of the urine did not influence the values obtained by the ELISA measurements . Industrial workers, exposed to trichloroethylene, were investigated for the occurrence of chronic tubular damages. The excretion of GST alpha in urine proved to be a very good marker to detect such damage and was more specific than other parameters such as alpha-1-microglobulin.