A comparison of RT-PCR and Northern blot analysis in quantifying metallothionein mRNA levels in killifish exposed to waterborne cadmium

Reverse transcriptase PCR (RT-PCR) was evaluated as an alternative to Northern blot analysis in quantifying levels of metallothionein (MT) mRNA. Killifish were exposed to water-borne cadmium (Cd) at concentrations ranging from 0 ppb to 46 ppb and their levels of hepatic MT mRNA were quantitated by both Northern blot analysis and RT-PCR. Both methods provided comparable results in that low constitutive levels of MT mRNA were observed in fish exposed to clean water, dose-responsiveness was seen in fish exposed to increasing concentrations of Cd, and sensitivities of both techniques were similar in detecting induced levels of MT mRNA in Cd exposed fish. These results suggest that RT-PCR may provide a sensitive and quantitative method to evaluate gene expression in fish from small, non-invasively sampled tissues.