Potassium effect on Na(+), K(+)-ATPase activity of cultured newborn rat astroblasts during differentiation.

High K(+) concentration effect on Na(+), K(+)-ATPase activity of cultured newborn rat astroblasts has been studied in conditions under which astrocytic differentiation could have taken place. In 14-day-old cultures, no potassium effect could be found reflecting the undifferentiated state of these cultures. After dibutyryl-cyclic AMP treatment, which induces a morphological transformation suggesting a differentiation, no K(+) effect appears but the specific enzyme activities are higher than in control cells reflecting the development of numerous cellular processes. After 28 days of cultivation - a cultivation period which closely corresponds to the time of astrocytic differentiation in vivo - Na(+),K(+)-ATPase activity at 25 and 50 mM K(+) concentrations are higher than at 10 mM, suggesting that an astrocytic differentiation has taken place in vitro.