Phosphatases and bone growth

By mapping the distribution of resorptive and appositional surfaces in rat skull bones with the help of in vivo staining with alizarin red S. it has been possible to study the connection between patterns of bone growth and alkaline and acid phosphatase activity on bone surfaces. Alkaline phosphatase activity obviously bears no specific relation to appositional and resorptive surfaces as all surfaces react strongly. Acid phosphatase activity, in contrast, is most marked at sites of resorption.