Final answer:
High potassium intake typically results in hyperkalemia only if potassium excretion is impaired, often due to abnormal renal function or diseases affecting the kidneys' ability to excrete potassium. The correct option is d) Potassium excretion is impaired
Step-by-step explanation:
High potassium intake leads to retention (hyperkalemia) only when potassium excretion is impaired. This impairment can occur due to factors such as renal failure, dehydration, and Addison's disease. The hormone aldosterone plays a significant role in this process. It increases the excretion of potassium and the reabsorption of sodium in the distal tubule. Aldosterone is released in response to high levels of potassium in the blood, low levels of sodium, or decreased blood pressure.
A negative feedback loop then occurs as the increased osmolality of the extracellular fluid, following aldosterone-stimulated sodium absorption, inhibits the release of the hormone. If kidney function is normal, even high dietary potassium does not normally lead to hyperkalemia due to the kidney's large capacity to excrete potassium. Thus, an impaired excretion mechanism, often associated with abnormal renal function, is necessary for hyperkalemia to occur in the context of high potassium intake. The correct option is d) Potassium excretion is impaired