Establishment of tissue culture cell strains from normal fetal human liver and kidney.

Three cells strains of tissue culture were established from normal fetal human liver and kidney tissues. The rate of cell proliferation decreased with time after the primary culture. The cells were rarely subcultured, but the medium was renewed routinely twice a week. After 9 months of cultivation, the cells were found in both tissues to have abruptly begun to proliferate rapidly, but only in the group culture in the medium containing galactose and sodium pyruvate in place of glucose. No special treatment were given to these cultures, e.g. treatment with viruses, chemical carcinogens and others. The chromosome number was kept around diploid in the beginning but was shifted to hypotriploid after the establishment. The cell strain from liver consists of epithelial cells. The cell strains from kidney consist of mixed population of various kinds of cells. Doubling time of cells is about 33.4 hours in all of them, as determined by cinemicrography. This might be the first establishment of cell strains from untreated, normal human tissues.