[In vitro electrophysiological determination of an individual ouabain sensitivity of human ovarian tumors].

In the standardized ouabain test (10(-4) mol/l, 2 h) 10 different cell cultures react with cell kind specific transmembrane potential (TMP) changes. Primary cultures of human embryo cells and skin transmembrane potential (TMP) changes. Primary cultures of human embryo cells and skin fibroblasts revealed the highest sensitivity (approx. 60-70% TMP reduction), while smaller and relatively low sensitivities were observed for permanent cells (approx. 30-40% TMP reduction) and white blood cells (approx. 20% TMP reduction), respectively. Unlike these cells, 36 human ovarian tumors showed interindividually varied reactions within the range of TMP changes from -55% to +33%. Especially, the majority of malignant tumors exhibited only a weak reaction in the ouabain test or no reaction at all. Ovarian cysts or clinically benign tumors showed a normal ouabain effect. The striking reactions of the ovarian tumor cells are believed to demonstrate a defect of one or several transport enzymes, especially of the (Na+/K+)-activated membrane ATPases. Possible correlations between the disturbed transport mechanisms of the cell membrane and the control of the cell growth and cell division are discussed.