63Ni[II]-incorporation into lung and liver cytosol of Balb/C mouse. An in vitro and in vivo study.

The kinetic studies of 63Ni[II]-incorporation in whole tissue show that after 6 days lung has the highest affinity to nickel of all studied organs. The same observation was made when 63Ni[II]-incorporation was carried out by 7 daily injections. In both experiments, kidneys take the second place in the relative distribution of nickel. For the studies of Ni-binding proteins in lung and liver cytosols, three different types of 63Ni[II]-incorporation were performed: (i) in vitro incorporation, (ii) kinetic study of in vivo incorporation where the animals were sacrificed after 30 min, 1, 2 and 4 h after a single i.p. injection of 63NiCl2, (iii) in vitro incorporation by 7 daily i.p. injections of 63NiCl2 with sacrifice of the animals 24 h after the last injection. Several Ni-binding proteins could be observed without regard to the type of incorporation performed. In liver cytosol most of these proteins can be revealed in vitro as well as in vivo. The in vivo labelled proteins are not the same at the beginning of the incorporation (30 min) and after an elapsed period (1 to 2 h). In lung cytosol in vitro and in vivo incorporation gave different results: although an intense labelling occurs after in vitro incubation, only few proteins are labelled after in vivo incorporation, two of which are only revealed after continuous exposure to 63Ni[II]. Most of the labelled proteins of lung and liver cytosols can be recovered after different fractionation experiments. These investigations confirm that nickel is preferentially bound to lung and demonstrate that nickel-incorporation is different in lung and in liver cytosols. It is shown here that several cellular proteins are implicated in the nickel-transport. The evolution of this phenomenon suggests the existence of a nickel-metabolism in the cell.