Flow Scheme of Ca um-EDTA
The cadmium-EDTA complex may be excreted
more readily in the urine and thus EDTA injection
may decrease renal concentrations of cadmium
(Fig. 5). However, an increased renal toxicity
may still be possible if EDTA is not provided in
sufficient amounts at all times to keep up the
cadmium-EDTA complex, so that no cadmium is
released in the kidney from the cadmium-EDTA
complex. If such release occurs, the already borderline
toxic concentration of nonmetallothionein-bound
cadmium that may be present in longterm
cadmium exposure may be increased. The
critical concentration for nonmetallothioneinbound
cadmium may thus be exceeded, and renal
toxicity may occur. An alternative explanation
for such renal toxicity may be that cadmiumEDTA
is more readily transferred to. the sensitive
sites where cadmium may be released from EDTA
and bound to the sensitive receptor