Final answer:
The differentiation from pre-osteoblasts to osteoblasts is regulated by growth hormone (GH) and hemopoietic growth factors, which are crucial in bone cell proliferation and bone density enhancement.
Step-by-step explanation:
The growth factor that allows pre-osteoblasts to differentiate into osteoblasts is influenced by several hormonal and growth factors. Osteogenic cells, which are the only bone cells that can divide, differentiate into osteoblasts with the help of these signals. Specifically, growth hormone (GH) from the pituitary gland increases calcium retention and stimulates osteoblastic activity for better bone density. Additionally, hemopoietic growth factors like erythropoietin and interleukins play a role in the differentiation and proliferation of cells that will become osteoblasts. As the process of bone formation commences, mesenchymal cells in the embryonic skeleton differentiate into osteogenic cells and then osteoblasts, forming an ossification center.