鉛によるラット肝亜鉛メタロチオネインの誘導

抄録

At 18 h after the single injection of lead acetate (100 mg/kg) in male Wistar rats, zinc content in the low molecular-weight protein fraction (zinc binding protein, Zn-BP) in the hepatic 105000g soluble fraction markedly increased, whereas lead was detected only in the high molecular-weight protein fraction by using Sephadex G-75 gel filtration. The properties of this Zn-BP were investigated and the following results were obtained. 1) Molecular weight was estimated about 10000 daltons. 2) Zinc in Zn-BP was substituted with cadmium. 3) UV spectrum of Zn-BP showed similar spectrum to metallothionein. 4) The formation of Zn-BP induced by lead was almost inhibited by the pretreatment with actinomycin D. 5) Zn-BP was heat-stable, when treated at 80°C for 1 min. These findings suggest that Zn-BP is thought to be zinc metallothionein (Zn-MT) and consequently lead has an inductive potency to Zn-MT in the liver of rats.