Which hormone increases osteoclast activity?

Which hormone increases osteoclast activity?

• A. Calcitonin
• B. Parathyroid hormone
• C. Growth hormone
• D. Estrogen

Answer: (B)

Rising parathyroid hormone signals bone to release calcium by boosting osteoclast activity. It acts on osteoblast lineage cells to shift the RANKL/OPG balance toward more RANKL and less OPG, which promotes differentiation and activation of osteoclasts. The result is increased bone resorption and calcium release into the bloodstream, helping restore calcium levels after a drop. Calcitonin directly inhibits osteoclasts, reducing resorption; estrogen lowers osteoclast lifespan and activity; growth hormone mainly promotes bone formation and remodeling with anabolic effects rather than increasing osteoclast activity. So the hormone that increases osteoclast activity is the parathyroid hormone.

Rising parathyroid hormone signals bone to release calcium by boosting osteoclast activity. It acts on osteoblast lineage cells to shift the RANKL/OPG balance toward more RANKL and less OPG, which promotes differentiation and activation of osteoclasts. The result is increased bone resorption and calcium release into the bloodstream, helping restore calcium levels after a drop. Calcitonin directly inhibits osteoclasts, reducing resorption; estrogen lowers osteoclast lifespan and activity; growth hormone mainly promotes bone formation and remodeling with anabolic effects rather than increasing osteoclast activity. So the hormone that increases osteoclast activity is the parathyroid hormone.