セレン同時投与によるカドミウム急性毒性軽減とメタロチオネイン

抄録

The present study was conducted to elucidate the protective action of simultaneous selenium administration against acute cadmium toxicity.
The remarkable testicular damages caused by cadmium, that is, hemorrhagic inflammation, atrophy and necrosis, were lessened by simultaneous selenium administration. Cadmium concentration in blood, especialy in plasma, increased significantly during the early period after cadmium administration with selenium. Cadmium and selenium in plasma were found in the same fractions of high molecular weight reported by previous workers as the high molecular weight complex containing cadmium and selenium. Cadmium in testis was also noted in the high molecular weight fraction during the early period. However, cadmium in the high molecular weight fraction of plasma and testis were unstable and decreased rapidly by lapse in time.
Cadmium concentration in liver was lower than that in the group administered cadmium alone during the increasing phase of plasma cadmium. However, in contrast with the decreased cadmium level in plasma, cadmium in liver and testis increased gradually. Cadmium increased in liver and testis were also found in the metallothionein fraction. In the testis protected from acute cadmium toxicity, the inhibitory effect of glutaghione S-transferase activity by cadmium was not detectable and the activity was maintained at the level of the control (saline administered group). Moreover, the increased cadmium in the metallothionein fraction was related to the decrease of cadmium in the high molecular weight fraction of the testis homogenate. In addition, a positive correlation was observed between metallothionein concentration and glutathione S-transferase activity.
These results strongly suggested that the protective action of simultaneous selenium administration against the acute cadmium toxicity was composed of the foregoing two processes and that metallothionein might play a secondary role in the protection.