Morphologic and biochemical characteristics of human kidney cells in vitro.
In vitro cultivated cells derived from normal human renal cortex were characterized morphologically and biochemically. Although the epithelial monolayer was composed of heterogeneous cells, it included cells with a surface structure similar to microvilli as well as some resembling the desmosome between neighboring cells. Enzymatic studies revealed a marked decrease in alkaline phosphatase activity, and the activity of gamma-glutamyl transpeptidase was also reduced to about one-fifth of that in the original tissue. The electrophoretic mobility of the enzyme was not identical with that of normal kidney or of the novel enzyme in renal neoplastic tissue. Lactate dehydrogenase activity was similar to that of normal kidney tissue but the isozyme pattern was completely inverted. These cells responded to the addition of 10 ng per ml of parathyroid hormone in culture medium and there was a 33 fold increase in intracellular cyclic adenosine monophosphate. Estrogen specific binding protein was not detectable in the monolayer cells. These results clearly indicated that the biologic transformation observed in the cultivated normal cells was not attributable to simple fetalism or dedifferentiation, but was a more complicated process.