4. Cells incubated in ouabain* for 24 hr bind an additional amount of ouabain when exposed to 2 x 10-7 M ouabain* in K-free Krebs.5. There is a close relationship between the % of the total ouabain bound in 24 hr and the % inhibition of the Na efflux suggesting that this ouabain is bound to the Na pumps.6 LESLEY J. BOARDMAN AND OTHERS 9. These results are compatible with the hypothesis that partial blocking of Na pumps leads to the production of more pumping sites by the cell.

SUMMARY1. HeLa cells were grown in normal and altered growth solutions; the ion contents, volumes, K sensitive ouabain binding, the Na-K-ATPase and the Na and K transport measured.2.

synopsisChanges in the erythrocyte membrane cation carrier following lithium ingestion in normal human subjects were studied; ouabain sensitive potassium influx fell significantly during the lithium treated phase. Lithium was fed to rats and no change in erythrocyte Na-K ATPase was shown. These findings contrast with studies of lithium in manic depressive psychosis. The fluctuations in the erythrocyte membrane cation carrier were studied in 5 normal subjects over 12 weeks and the correlations between the parameters calculated. The erythrocyte sodium concentration correlated positively with the ouabain sensitive potassium influx. This too contrasts with findings in manic depressive psychosis.

SynopsisErythrocyte sodium and potassium concentrations, erythrocyte membrane ATPase (Na–K specific and non-specific) and the rate of potassium influx into erythrocytes (ouabainsensitive and insensitive) were estimated in a group of female patients suffering from mania and repeated on about two thirds of them when they had recovered. With recovery there was a statistically significant increase in the erythrocyte ouabain-sensitive potassium influx. The other parameters showed no significant overall change with recovery but the initial severity correlated significantly and negatively with the change in erythrocyte Na–K ATPase with recovery. The changes that occurred in the erythrocyte sodium concentration and Na–K ATPase activity were not random since they correlated significantly with changes in the active potassium influx.

1. HeLa cells were grown for 24 hr in growth medium in which part of the Na was replaced with Li. Ion contents, cell volumes and numbers, Na‐K‐ATPase and specific ouabain binding were measured. In some experiments the Na efflux and net Na transport was also measured. 2. Growth in Li caused a rise in the specific ouabain binding and membrane Na‐K‐ATPase of these cells. The Li concentrations in the cells necessary to produce this effect ranged up to 50 mM. 3. It is suggested that Li, like Na, acts on the genetic material of the cells to cause the production of more Na pumps within the membrane.