D-penicillamine induces rat hepatic metallothionein

Intraperitoneal injection of D-Penicillamine (D-PA) at a dose range of 20-500 mg/kg increased rat hepatic but not renal and pancreatic metallothionein (MT). Elevated MT predominantly contained Zn. Maximal induction was obtained 18 h after a single injection of 200 mg D-PA/kg resulting in 148 ± 18 μg MT/g liver which was 16.4-times the control level of 9 ± 2 μg MT/g. At 48 h after injection, MT declined to 18 ± 9 μg MT/g liver. At maximal MT increase the content of total hepatic Zn but not of Cu was elevated. Increased amounts of Zn in liver homogenate, cytosol and MT could be detected approximately 4 h after injection of 200 mg D-PA/kg. Concomitantly there was a decrease in Zn bound to cytosolic non-MT ligands. All Zn changes reversed at 18 h. These data show that already single doses of D-PA cause induction of Zn-thionein in rat liver and lead to synchronous redistribution of Zn from endogenous sources to newly synthesized MT.