Histidine-rich glycoprotein in the blood of the bivalve Mytilus edulis: role in cadmium speciation and cadmium transfer to the kidney

Cadmium transfer from M. edulis L. blood plasma to tissues was investigated in relation to its chemical speciation in the blued. Cd-109 was injected i nto the posterior adductor muscle along with synthetic chelators oxine, eth ylene-diaminetetraacetic acid (EDTA) or cyclohexanediaminetetraacetic acid (CDTA). Chelator concentrations were chosen to bind up from 0 to 98.7% of t he total blood Cd, based on speciation calculations using the geochemical s peciation model MINTEQA3. Increases in synthetically chelated Cd were accom panied by linear decreases in the calculated percentages of Histidine-rich Glycoprotein (HRG)-bound Cd, and nonlinear decreases in Cd2+ and Cd chloro- complexes. Cadmium uptake by the kidneys decreased with increasing percenta ge synthetic chelation, while uptake by other tissues was not affected by c helation. Results indicate that there is at least one mechanism of Cd uptak e common to all M. edulis tissues, and an additional, more rapid uptake mec hanism in the kidneys that is mediated by CdHRG. (C) 2001 Elsevier Science B.V. All rights reserved.