Two hundred and sixteen young adult male Sprague‐Dawley rats, 80+5 days old, and each weighing approximately 220–250 gm, were injected IP every 3 days for 29 days for a total of 9 injections with 0, 1.0, or 2.5 mg CdCl2/kg body weight. Total cumulative doses were 0, 9.0 or 22.5 mg CdCl2/kg body weight. Twenty‐four hours after the last cadmium injection (day 30), each rat was irradiated with a total‐body exposure of 0, 3.62, or 5.43 Gray of gamma (60CO) radiation at a dose rate of 3.04 Gray/min. Eight rats from each of the 9 groups were sacrificed on day 1, 7, or 21. Highest levels of the creatine kinase enzyme were seen in radiation groupsatday 1, indicating an immediate radiotoxic response. Enzyme levels decreased through day 21 indicating clearance of the enzyme from the plasma. Although statistically significant differences between the groups, cadmium, radiation, or days were not seen, cadmium did protect against radiation. This protective function is not explainable; however, we speculate that different conformations of metal‐induced metallothioneln clusters exist to accommodate various metal ions. Further, that each kind of metal ion may have different and unique distribution patterns between the cluster centers which account for different functions.