Lithium incorporation in the fibroblasts of manic-depressives.
Lithium incorporation in cultured human skin fibroblasts was measured in a group of 10 manic-depressives and 10 controls. This system was believed to eliminate many of the sources of variability to which measurement of the lithium ratio in erythrocytes (RBCs) is subject. A fibroblast lithium ratio calculated from 1-hr lithium incorporation studies correlated highly with an in vitro RBC lithium ratio in medication-free controls. Manic-depressives and controls did not differ in lithium incorporation or fibroblast lithium ratio, leading to the conclusion that the lithium ratio is probably not a good measure for differentiating the two populations.