Final answer:
Aldosterone action on principal cells leads to sodium reabsorption and potassium excretion, increasing blood volume and pressure. Hence, the associated action is increased potassium secretion.
Step-by-step explanation:
The actions of aldosterone on principal cells in the kidney are crucial for regulating electrolyte balance and blood pressure. One of the primary effects of aldosterone is to prompt the kidneys to reabsorb sodium, which leads to increased retention of water, consequently increasing blood volume and blood pressure. Another significant action of aldosterone on principal cells is to increase the excretion of potassium, which balances electrolyte levels in the body. Aldosterone does not promote increased urine output; instead, its role is to conserve water by reducing the excretion of sodium. It is also essential in maintaining proper blood and plasma osmolarity, and it is not directly associated with calcium reabsorption in the kidneys.
Considering the options provided in the student's question, the correct answer is that aldosterone is associated with increased potassium secretion (2), as it promotes the excretion of potassium from the body.