Metallothionenein (MT) is produced in the liver after the organism exposed to heavy metals. MT is involved in homeostasis and detoxification process of heavy metals. Thus, MT has the potential to be applied as a bioindicator for heavy metal exposure of the organisms especially the aquatic ones. MT is characterized based on a high content of sulphur, cadmium and zinc. In present, the assessment on heavy metal contamination can be used to detect MT both directly and indirectly, i.e. (1) direct methods: the measurement of MT content by the difference pulse polarography (DPP) and spectrophotometry and (2) indirect methods: the measurement of MT content in each organ of aquatic organism by using antibody technique such as Enzyme-linked immunosorbent assay (ELISA) or western blot. The measurement on expression level of gene controlling MT production by many biomolecular techniques allowing to evaluate heavy metal exposure condition of the organism. In Thailand, the study on MT and its application have been inadequate. There were two cases of MT application as biomarker found: Ang sila (Chonburi province) and Map ta put (Rayong province). Thus it should be more studied for developing and extending its application.
Keywords: Metallothionein, Biomarker, Heavy metal, Aquatic organisms