Fate of kidney metallothionein intraperitoneally injected into the rat.

Abstract

Rat kidney metallothionein, which contains Cu as a major metal, was injected into young female rats to investigate whether the injected kidney metallothionein is degraded and re-synthesis of metallothionein occurs in the kidneys, as in the case of injected liver metallothionein. The changes in the gel filtration profiles of the kidney supernatant fractions with time could be explained by the degradation and re-synthesis of metallothionein in the kidneys. The Cd and Cu liberated from the degraded metallothionein induced the biosynthesis of metallothionein and Cu-binding protein (possibly copper-thionein). The resynthesized metallothionein was only rich in Cd and Zn and the half-lives of the 2 metals were long. The half-life of the Cu-binding protein was short. The peak positions of the metallothionein and the Cu-binding protein were different on a Sephadex G-75 column. The renal tubular lining cells were severely demaged by metallothionein injection. The necrosis and recovery of the kidneys were confirmed by microscopic examinations and by analysis of urinary glucose.