Comparison of polarography and radioimmunoassay for the quantification of metallothionein in perch (perca fluviatilis)

Two methods to quantify metallothionein (MT), differential pulse polarography (DPP) and radioimmunoassay (RIA), were compared for MT analysis of livers from ZnCd-injected perch ( Perca fluviatilis ). There was a strong agreement in the results obtained by the two methods. The regression line for the plot MT RIA versus MT DPP is described by the formula: MT RIA = (MT DPP × 0·99)—0·048 (r = 0·92). When the MT value of each 200 mg tissue sample was divided by the value of corresponding 100 mg tissue sample, the quotient was 1·70±0·78 for DPP and 1·86±0·34 for RIA (mean±SD). MT values, from individual liver samples, plotted against the Cd and Zn content of the corresponding samples provided a slightly lower correlation coefficient for MT values measured by DPP ( r = 0·87), than by RIA ( r = 0·92).