engleski

Correlation of biometric parameters with metallothionein and cytosolic metal levels (Zn, Cu, Cd) in liver, kidney and brain of Mullus surmuletus and Liza aurata from the Eastern Adriatic Sea

The present study was initiated as the collaborative project with Norwegian Institute for Water Research to define the fluctuations of metallothionein (MT) and metal levels in liver, kidney and brain of two wild fish species, representative for the Eastern Adriatic Sea. The studied marine area (Kastela Bay) is affected by industrial and domestic wastewater inputs. Fish tissues of Mullus surmuletus (striped red mullet), benthic species and Liza aurata (golden gray mullet), pelagic species, were homogenised and centrifuged at 50000xg to get cytosolic fraction (S50) which was appropriately diluted, heat-treated and analysed on MT and metal (Zn, Cu, Cd) content. MTs were analysed by differential pulse polarography and metals by flame atomic absorption spectrometry. The results show species and tissue dependence. Highest MT and metal levels are determined in liver of Liza aurata (0.39 +/- 0.06 milligram MT/millilitre S50 ; 6.46 +/- 3.45 microgram Cu/millilitre S50) and in kidney of Mullus surmuletus (0.57 +/- 0.15 milligram MT/millilitre S50 ; 1.13 0.50 microgram Zn/millilitre S50). Our results support the role of liver and kidney as main detoxification organs. Correlation between metals and MTs is statistically significant for essential metals, especially Cu (0.69) in Liza aurata and Zn (0.95) in Mullus surmuletus suggesting that all metal binding sites of MT are not occupied yet. Total length, body weight and age are highly correlated biometric parameters with MT and soluble metal levels, which show increasing trend in liver of both species, indicating possible accumulation during life stage. These results emphasise the importance of considering additional factors, such as biometric parameters, in the survey of endogenous and exogenous factors, which are involved in cellular effects of metals.

metallothioneins; biometric parameters; fish

DOI: doi:10.1016/j.marenvres.2004.03.007