Immunochemical and immunohistochemical studies of cadmium associated proteins in Rana tadpoles.

Previous observations suggested that Rana tadpoles treated with aqueous cadmium (Cd) accumulate Cd in their liver and mesonephros. In order to study the response to Cd in these tissues we (a) exposed tadpoles in mid-limb bud stages to sublethal quantities of Cd, (b) isolated Cd-associated protein (CAP) from a liver cytosol fraction, (c) prepared a heterologous rabbit antiserum against glutaraldehyde-treated CAP (G-CAP), (d) used the rabbit anti-G-CAP antiserum in order to assess the tissue distribution of CAP in Cd-treated and untreated tadpoles, and (e) assessed species cross-reactivities of our anti-G-CAP with CAPs and metallothioneins (MTs) isolated from Cd-treated vertebrate liver cytosol fractions. We found that (a) CAP was present in higher quantities in liver cytosol obtained from Cd-treated tadpoles compared to liver cytosol obtained from untreated control tadpoles, (b) indirect immunofluorescent analysis revealed that CAP was localized in liver hepatocytes and kidney tubule epithelial cells in Cd-treated tadpoles, and (c) the anti-G-CAP crossreacted with rodent and fish CAP. These observations suggest that the developing liver and mesonephros are involved in responses to toxic metals and that our anti G-CAP antiserum may be used to gauge exposure to environmental Cd.