Relationship between Glutathione Levels and Activities of Detoxification Enzymes in Anopheles gambiae from Northwest Nigeria

Aims: The aim of this study is to investigate the relationship between levels of the three forms of glutathione and the activities of detoxification enzymes in Anopheles gambiae from northwest Nigeria.

Study Design: Anopheles gambiae larvae were sampled from breeding sites with marked differences in physico-chemical characteristics, grouped into three different study zones A, B & C on the bases of human related activities (intensive agriculture, domestic, and petrochemical activities, respectively) taking place within and/or around the breeding sites. The sampled larvae were reared until they emerged into pupae and adult.

Place and Duration of Study: Department of Biochemistry Bayero University Kano, Abertay Centre for Environment, University of Abertay Dundee, between June 2011 and May 2013.

Methodology: Activities of the 3 major detoxification enzymes (P450, GST and α & β-esterases) were assayed on the sampled larvae and the emerged pupae and adult followed by the determination of the levels of total, oxidized and reduced glutathione across the three life stages.

Results: Following various statistical analyses, the activities of the detoxification enzymes were higher in zones A and C (which also recorded higher levels of the physico-chemical factors) compared to zone B. Also, the relative distribution of glutathione showed that the levels of total and reduced GSH across the three study zones appeared to be similar while the levels of oxidized glutathione (GSSG) appeared to be higher in study zone A and C compared to zone B. A deduced statistical model established the different forms of the glutathione variables as having a significant effect on the activities of the detoxification enzymes across the three life stages of An gambiae from northwest Nigeria.

Conclusion: These observations could allow for an evaluation of the possibility of targeting control of the activities of detoxification enzymes in mosquitoes through manipulation of the availability of GSH in the management of insecticides resistance in mosquitoes.