Figures 3–4. Figure 3. Alkaline phosphatase–specific activity of osteoblast precursor cells in control media without additional calcium (Ca) or inorganic phosphorous (Pi) addition, in media with additional high and low Ca addition, and in media with additional high and low Pi addition. Figure 4. Osteocalcin production of osteoblast precursor cells in control media (without additional Ca or Pi addition), in media with additional high and low Ca addition, and in media with additional high and low Pi addition