Which hormone stimulates cellular activity in bone tissue?

The hormone that primarily stimulates cellular activity in bone tissue is parathyroid hormone (PTH). PTH is secreted by the parathyroid glands and plays a crucial role in regulating calcium levels in the blood. It promotes the activity of osteoclasts, which are cells responsible for bone resorption, thereby increasing the release of calcium from bones into the bloodstream. Additionally, it enhances the absorption of calcium in the intestines and reabsorption in the kidneys.