**Core Concept**
Cinacalcet is a calcimimetic agent that works by activating the calcium-sensing receptor (CaSR) on the surface of parathyroid gland cells. This activation leads to a decrease in parathyroid hormone (PTH) secretion, which is elevated in conditions such as secondary hyperparathyroidism.

**Why the Correct Answer is Right**
Cinacalcet binds to the extracellular domain of CaSR, mimicking the action of calcium ions and increasing the sensitivity of the receptor to calcium. This results in a decrease in PTH secretion, which helps to reduce hypercalcemia and hyperphosphatemia associated with secondary hyperparathyroidism. Cinacalcet is primarily used in the treatment of secondary hyperparathyroidism in patients with chronic kidney disease on hemodialysis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because cinacalcet does not work by inhibiting the reabsorption of calcium in the kidneys.
**Option B:** This option is incorrect because cinacalcet does not work by increasing the excretion of calcium in the urine.
**Option C:** This option is incorrect because cinacalcet does not work by directly inhibiting PTH production.

**Clinical Pearl / High-Yield Fact**
Cinacalcet is a useful option for patients with secondary hyperparathyroidism who are resistant to vitamin D analogs or have severe hypercalcemia.

**Correct Answer:** C.