Soluble glutathione S-transferases from rat testes: isoenzyme pattern and lack of inducibility by drug metabolizing enzyme inducers.

The soluble glutathione S-transferase (GST) isoenzymes from rat testicular tissue were separated in one chromatographic run on carboxymethyl cellulose. GST was measured with 1-chloro-2,4-dinitrobenzene as the second substrate. The following percentages for the different isoenzymes were found: GST AA: 12.6%, GST A:8.1%, GST B:4.2%, GST C:18.1%, GST D and E: not detected, GST x:7.4%, and anionic GST:49.6%. These values were quite different from those found in liver tissue. Testicular GST could not be induced by the drug metabolizing enzyme inducers trans-stilbene oxide, DDT, and phenobarbital. The high GST content in rat testes may suggest that these enzymes function also in this tissue in the metabolism and detoxification of electrophilic xenobiotics.