Biochemical and histochemical features of human cultured cells (EUE) adapted to hypertonic medium

EUE cells from a human heteroploid line cultured in hypertonic medium (0.274 M NaCl) modify their lipid pattern: sulfolipid concentration reaches 86 to 90 microgram/mg protein whilst it ranges between 19 to 32 microgram/mg in cells cultured in isotonic medium. Ganglioside concentration reaches 2.6 nmoles of sialic acid/mg protein (after 75 days) and 13 (after 85 days) in hypertonic saline medium. Whilst it is 0.5 in isotonic medium. Phospholipid concentration does not show any similar change. Cytoenzymatic analysis reveals that dehydrogenases (lactate, G-6-P dehydrogenases, tetrahydrofolate reductase and NADH diaphorase) appear strongly enhanced in cells grown on hypertonic medium. On the contrary higher acid phosphatase and ATPase activity was demonstrable in cells grown on isotonic medium. These results are similar (except for ATPase activity) to those observed in salt secreting glands involved in strong osmotic work. The results are discussed in relation to the problem of energy supply in cells performing osmotic work.