Gamma aminobutyric acid radioreceptor‐assay a possible biomarker for human exposure to certain agrochemicals |
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Authors: | Mahmoud A Salen M Abou Zied G El‐Baroty E Abdel‐Reheim Fawzia Abdel‐Rahman C Wallace |
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Institution: | Environmental Chemistry and Toxicology Laboratory, Department of Chemistry , Texas Southern University , Houston, TX, 77004 |
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Abstract: | Abstract Cyclodiene insecticides, hexachlorocyclohexanes, pyrethroids, bicyclophosphates, the bicycloorthocarboxylate insecticides and some of their metabolites and environmental degradation products are central nervous system toxicants with high specific binding affinity to the chloride channel of the γ‐ aminobutyric acid (GABA)A receptor‐ionophore sites. 35S] tertiary‐butylbicyclophosphorothionate (TBPS) with specific activity higher than 60 Ci/mmole has a high binding affinity to the same sites and is now commercially available and can be used to label the GABAA receptor for the development of a radioreceptor assay technique. The GABA receptor was prepared by ultra centnfugation and dialysis of brain homogenates of either cow, goat, rat or catfish. The receptor was then labeled with 35S] TBPS and the assay was conducted by measuring the displacement of radioactivity following incubation with samples containing the analytes. A radioreceptor assay protocol was developed to measure the amount of the α‐endosulfan in blood samples. The assay was extremely sensitive, and can detect 0.2 nM of endosulfan at a level equivalent to 0.08 ppb or 8x10‐11 gm of endosulfan in each ml of the blood samples. |
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Keywords: | Gamma Aminobutyric Acid Radioreceptor Assay Endosulfan Cyclodienes Biomarker Human exposure Human blood Rat Goat Cow Catfish |
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