A luminescence probe for metallothionein in liver tissue: emission intensity measured directly from copper metallothionein induced in rat liver

We report the first use of an emission probe based on the Cu(I)-thiolate chromophore, for the direct observation of copper metallothionein located in samples of rat liver. Elevated synthesis of Cu-MT in the rat liver was induced by subcutaneous injections of a series of aqueous CuCl 2 solutions containing increasing amounts of Cu(II). Luminescence intensity in the 600 nm region, detected from frozen solutions of Cu-MT and from slices of the liver frozen at 77 K, following excitation in the 300 nm region, was dependent on the concentration of the Cu(II) used in the inducing solution. No such luminescence intensity was found for control samples obtained from the livers of rats not exposed to copper salts. It is suggested that this new method will allow direct visualization of Cu-MT in tissue where genetic disorders impare copper metabolism.