**Core Concept**
Primary hyperaldosteronism is a condition characterized by the excessive secretion of aldosterone from the adrenal glands, leading to hypertension and hypokalemia. This excessive secretion is often due to an aldosterone-producing adenoma, which stimulates the renin-angiotensin-aldosterone system (RAAS).

**Why the Correct Answer is Right**
Primary hyperaldosteronism is characterized by the excessive production of aldosterone, which leads to sodium retention and potassium excretion in the kidneys. This results in hypertension and hypokalemia. The increased renin levels in primary hyperaldosteronism are a response to the decreased levels of aldosterone, which is a negative feedback mechanism.

**Why Each Wrong Option is Incorrect**
**Option A:** Hypocalcemia - This is incorrect because primary hyperaldosteronism typically leads to hypercalcemia due to the increased calcium absorption in the kidneys.

**Option B:** Hyperinsulinemia - This is incorrect because primary hyperaldosteronism is not directly related to insulin secretion.

**Option C:** Hyperuricemia - This is incorrect because primary hyperaldosteronism can lead to hypouricemia due to the increased excretion of uric acid in the kidneys.

**Clinical Pearl / High-Yield Fact**
Primary hyperaldosteronism is often associated with a low renin level, which is a key differentiating feature from secondary hyperaldosteronism.

**Correct Answer:** D. Hypocalcemia