The relationship between metallothionein and intestinal zinc absorption in the winter flounder

Abstract

Chromatographic techniques were used to investigate the presence of zinc-binding proteins in the intestinal mucosal cytosols of a marine teleost, the winter flounder (Pseudopleuronectes americanus). A low molecular weight, zinc-binding protein, characterized as metallothionein, was isolated from the intestinal cytosols of zinc-injected flounder. Metallothionein synthesis was induced in the intestine of the flounder by parenteral injections of zinc. However, studies conducted to assess the involvement of metallothionein in gastrointestinal zinc uptake indicated that its presence in the intestinal cytosol was not associated with any enhancement or depression of zinc uptake. These findings contrast with current hypotheses concerning metallothionein function in mammalian intestines.