ATPase ACTIVITY OF NEUROBLASTOMA CELLS IN CULTURE

Abstract —Neuroblastoma cells were cultured in the presence of fetal serum. When serum was omitted from the growth medium and also when dibutyryl cyclic AMP or insulin were added without omitting serum, there was a growth of neuron‐like processes which was in most cases accompanied by an increase in Na+‐K+ ‐ATPase activity, whereas Mg2+‐ATPase activity increased to a lesser extent. The increase in ATPase activities was related to cell density. When the ATPase activities were measured in the presence of 0·25 m‐sucrose or 1% deoxycholate the specific activities were decreased. There was no loss of activity during storage at –20°C for several days when 20% glycerol was added to the medium.