Determination of Glutathione S-Transferase u Genotype in Humans by PCR-Amplified Gene-Probes

Hereditary polymorphisms are well known among enzymes of both phase-I and -II of foreign compound metabolism [5]. Thus, 10% of the middle European population are deficient of cytochrome P-450IID6, an isoenzyme metabolizing debrisoquine, sparteine, several tricyclic antidepressants, neuroleptics, s-blockers, etc. Among the Japanese, less than 1% are deficient, pointing to ethnic differences. Another example of polymorphic enzyme expression concerns the newly sequenced liver N-acetyltransferase. 55% of Caucasians and 10% of the east Asean population exhibit a low activity of this phase II-enzyme. All these enzymes are not only involved in detoxication and toxifica-tion reactions of certain endogenous compounds but also of drugs and other xenobiotics including many carcinogens [5,7].