What effect does aldosterone have on potassium levels in the kidneys?

Aldosterone plays a crucial role in regulating electrolyte balance in the body, specifically influencing sodium and potassium levels. When aldosterone is present, it promotes the reabsorption of sodium ions in the kidneys' distal convoluted tubules and collecting ducts. This process is coupled with an increase in the excretion of potassium ions. Essentially, aldosterone enhances the activity of sodium-potassium pumps, leading to sodium being retained and potassium being secreted into the urine.

This dual function helps to maintain homeostasis, particularly in response to conditions such as high potassium levels or low sodium levels. By facilitating the excretion of excess potassium, aldosterone contributes to reducing potassium concentrations in the bloodstream, thereby helping to prevent hyperkalemia (elevated potassium levels), which can be dangerous.

In contrast, other options imply actions that are inconsistent with aldosterone's physiological role regarding potassium levels, such as retaining potassium or having no effect, which do not accurately reflect the hormone’s known regulatory impact.