Uptake and intracellular distribution of lanthanum.

The present investigation of the cellular distribution of lanthanum was undertaken in order to control the validity of the "Lanthanum method" used for the study of the cell calcium compartments. The presence of lanthanum was evaluated in the isolated guinea-pig heart and its subcellular fractions perfused with a lanthanum-containing Tyrode solution. Lanthanum was determined by instrumental neutron activation analysis. Under the adopted experimental conditions (30-min incubation in the presence of 12.5 microM lanthanum), lanthanum is carried across the cell membrane and is taken up by subcellular organelles. These results confirm the limited validity of investigations based on of the "Lanthanum method".