Effects of incubations in low potassium and low sodium media on Na-K-ATPase activity in snake and chicken kidney slices

1. 1. Effects of incubating snake and chicken kidney slices in media of varying potassium and sodium concentrations on the sodium-potassium-activated adenosine triphosphatase (Na-K-ATPase) activity of these slices were evaluated. 2. 2. Prolonged (2-hr) incubation of chicken kidney slices in potassium-free medium produced significant residual depression in Na-K-ATPase activity in heavy microsomes. Similar incubation of snake kidney slices in potassium-free medium had no residual effect on Na-K-ATPase activity. 3. 3. When potassium-depleted chicken kidney slices were incubated in the media of increasing potassium concentration, heavy microsomal specific Na-K-ATPase activity increased, but did not approach control value until medium potassium reached 40 mM. Recovery of Na-K-ATPase activity paralleled recovery of tissue potassium, suggesting the two may be related. 4. 4. Incubation of chicken slices in potassium-free medium had no residual effect on whole homogenate specific Na-K-ATPase activity, although all values were low. 5. 5. Incubation of chicken and snake kidney slices in low sodium medium had no residual effect on Na-K-ATPase activity.