Metabolism of cisplatin in the organs of Rattus norvegicus: role of Glutathione S-transferase P1.

Glutathione S-transferases (GSTs) play an important role in the biotransformation of endogenous compounds and xenobiotics as well as in the metabolic inactivation of pharmacologically active substances, including anticancer drugs. Using cisplatin as the prototype drug, we investigated if any correlation exists between GSH levels, GSTs/GSTP1 activity and the fate of cisplatin in different organs of Rattus norvegicus. GSH-cisplatin complex was prepared, purified by anion-exchange chromatography and subjected to mass spectroscopic analysis which confirmed the structure to be diglutathione-monoplatinum (diglutathionylplatinum). Purified diglutathionylplatinum was used to quantify metabolite formed in different tissue homogenates. Specific GSTP1 activity was found to be highest in kidneys, which correlated positively with the levels of metabolite formed in renal tissues. Altogether, our results showed that cisplatin metabolism in different organs of rats correlated positively with specific GSTP1 activities and this enzyme may be a critical determinant of extent of cellular uptake or retention of cisplatin in renal and liver tissues.