Metallothioneins in liver of Rutilus rutilus exposed to Cu2+. Analysis by metal summation, SH determination and spectrofluorimetry

Metallothioneins (MTs) have important roles in the homeostasis of essential metals and in the detoxication of heavy metals. They also represent a pote ntial indicator of aquatic contamination by metals. Routine methods are nee ded for MTs quantification in ecotoxicological studies. This paper investig ates the possibility to use the spectrofluorescent properties of Cu-MTs for MTs quantification. Cu displacement of metals coordinated to MTs and spect rofluorimetric determination of the obtained Cu-MTs was tested with commerc ial MTs and Cu2+ -induced MTs in roach liver (Rutilus rutilus). Results of this original and simple spectrofluorimetric quantification of MTs presente d a good correlation with data obtained with SH quantification, but not wit h metal summation evaluation of MTs (analysis of Zn, Cu and Cd coordinated to MTs), The three methods showed an clear induction of MTs in roach liver after 7 days of Cu2+ exposure. After 14 days of contamination, a reduction of hepatic MTs content was observable and not correlated to liver recovery. Results show that this low cost spectrofluorimetric method is useful to qu antify MTs. (C) 2000 Elsevier Science Inc. All rights reserved.