K secretion when Na intake changes
The effect of increased tubular flow rate is especially important in helping to preserve normal
potassium excretion during changes in sodium intake. For example, with a high sodium intake, there is
decreased aldosterone secretion, which by itself would tend to decrease the rate of potassium
secretion and, therefore, reduce urinary excretion of potassium. However, the high distal tubular flow
rate that occurs with a high sodium intake tends to increase potassium secretion. Therefore, the two effects of high sodium intake, decreased
aldosterone secretion and the high tubular flow rate, counterbalance each other, so there is little
change in potassium excretion.