Question

Which of the following is correct for thyrocalcitonin?

• A. Produced by thyroid and increases $C{a}^{2+}$in ECF.
• B. Produced by thyroid and decreases $C{a}^{2+}$ in ECF.
• C. Produced by parathyroid and increases $C{a}^{2+}$ in ECF.
• D. Produced by parathyroid and decreases $C{a}^{2+}$in ECF.

Answer 1

The correct option is B Produced by thyroid and decreases $C{a}^{2+}$ in ECF.

Thyrocalcitonin (TCT) is secreted by parafollicular cells of the thyroid gland. It is a protein hormone that lowers the blood calcium (hypocalcemia) and phosphate levels in blood plasma(ECF- Extracellular fluid) and promotes the formation of bone. The action of thyrocalcitonin is opposite to parathyroid hormone, which increases the level of calcium (hypercalcemia) in the blood plasma by releasing it from the bones.