[Study on urinary gamma-GTP activities as an indicator of cis-diamminedichloride platinum nephrotoxicity]

Acute change in urinary gamma-glutamyl transpeptidase (GTP) activity following cis-diamminedichloride platinum (CDDP) administration was studied in 12 patients who had malignant tumors. The activities were measured for 11 days from the day before CDDP administration and were expressed as IU/day. In all cases, the gamma-GTP activity increased with CDDP administration and decreased after completion of chemotherapy. Two peaks of gamma-GTP activity following CDDP administration were observed in many cases. In cases presenting with high gamma-GTP activity and low creatinine clearance before CDDP administration, the increase in the activity was prominent. The gamma-GTP activity before CDDP administration was significantly correlated with the gamma-GTP activity during the 10 days. This study suggests that the measurement of urinary gamma-GTP activity is important for the evaluation of CDDP nephrotoxicity, especially in cases of high gamma-GTP activity before CDDP administration.