A radioimmunoassay for perch (Perca fluviatilis) metallothionein.

A sensitive radioimmunoassay (RIA) for the measurement of metallothionein (MT) from perch (Perca fluviatilis) has been developed. The method is a double-antibody RIA with rabbit anti-perch MT serum as first antibody, goat anti-rabbit immunoglobulin G as second antibody, and perch MT conjugated to 125I-labeled Bolton-Hunter reagent as tracer. The rabbit antiserum raised against perch MT recognizes rainbow trout (Oncorhynchus mykiss) MT, but shows little cross-reactivity with horse MT. At a dilution of 1:2000, the MT antibodies bind 36% of the tracer when no cold ligand is present. The sensitivity of the assay is 15 pg perch MT per tube and the practical working range is 0.15-250 ng perch MT per tube. The RIA allows determination of MT in plasma or lysed blood cells at concentrations as low as 3.0 ng/ml and in tissues at levels above 9.0 ng/g (wet weight). Intra- and interassay coefficients of variation were 6 and 10%, respectively.