Effect of hydrocortisone and thyroxine on ATPase activities of neuronal and glial cell lines in culture

The effect of hydrocortisone and thyroxine, on the activities of Ca²⁺-and Mg²⁺-ATPase was studied in cultured neuronal (clone M1) and glial (clones NN and C6) cell lines. For M1 and NN cells an increase in Ca²⁺-and Mg²⁺-ecto-ATPase activity was found when the cells were cultured during 4–6 days in presence of hydrocortisone or together with thyroxine. In the same conditions, a decrease in Ca²⁺-and Mg²⁺-ecto-ATPase activity was found for the C6 cells. In C6 cells the effect of hormones was more pronounced for the Mg²⁺-than for the Ca²⁺-ecto-ATPase activity. The observed decrease may be related to the tumoral origin of the C6 cells. The activity of (Na⁺, K⁺)-ATPase in all three cell lines increased in presence of hydrocortisone or together with thyroxine when the cells were cultured during 4–6 days, in presence of the hormones, whereas the total Mg²⁺-ATPase activity increased only after 6 days of treatment. Thyroxine alone has very few effect either on Ca²⁺-and Mg²⁺-ecto-ATPase, or on (Na⁺, K⁺)-and total Mg²⁺-ATPase activity. These observations are interpreted to indicate that hormones may modulate or induce enzymatic activities involved in active transport phenomena in nervous tissue.