PHENOTYPING OF THE GLUTATHIONE-S-TRANSFERASE-M1 POLYMORPHISM IN ZIMBABWEANS AND THE EFFECTS OF CHLOROQUINE ON BLOOD GLUTATHIONE-S-TRANSFERASE-M1 AND GLUTATHIONE-S-TRANSFERASE-A

The frequency of the null allele phenotype of glutathione S-transferas e (GST) M1 was investigated in 114 Zimbabweans and results for a subse t of 63 subjects were compared with genotyping by PCR. In addition, th e effect of the antimalarial chloroquine on blood levels of GSTM1 and GSTA in 19 subjects was studied. Quantification of GSTs was by enzyme linked immunosorbent assays (ELISA). Thirty percent of the subjects we re of the GSTM1 null phenotype. Comparison of results of phenotyping b y ELISA and genotyping by PCR showed that 16% of samples were in disco rdance; unknown mutations in the GSTM1 gene in the Zimbabwean populati on may explain this observation. Chloroquine decreased levels of blood GSTM1 and GSTA by 50% or more. In populations treated with chloroquin e, these decreases in GST activities might lead to compromised ability to detoxify xenobiotics, could confound GSTM1 phenotyping and might i nvalidate use of GSTA as an indicator of liver damage. (C) 1997 Elsevi er Science B.V.