Specificity of zinc pathway in the rabbit: zinc-cadmium exchange

Marked perturbations of Zn 65 clearance curves and subsequent blood and tissue radioactivity levels were produced in rabbits by the injection of either ZnSO 4 or of CdSO 4 carriers. The responses to challenge with cadmium loading, although not identical, were sufficiently similar to those obtained with zinc to suggest that cadmium may be an antimetabolite for zinc. In contrast, no deviations from control experiments were produced by injections of CuSO 4 , Ga(C 2 H 3 O 2 ) 2 , or HgCl 2 . Hence, those segments of the physiological pathway of zinc through the body that were tested by these experiments proved to have sufficient specificity to discriminate completely against these latter elements.