The effect of temperature on potassium equilibria in chick embryo muscle.

The effect of temperature upon the exchange rates between intra- and extracellular potassium in chick embryo muscle was determined by the use of radioactive potassium. The temperature coefficient of at least four-fifths of the cell potassium is large. At temperatures below 15 degrees C., potassium is lost from the cell and is regained on warming. The results suggest the possibility that 20 per cent or less of the cell potassium may differ from the rest by being more rapidly exchangeable with the medium.