Changes in tissue concentration of prostaglandins during endochondral bone differentiation

Prostaglandins are known to be involved in bone metabolism as evidenced by the ability of PGE₂ to induce bone resorption. It was, therefore, of interest to determine if there was an association of specific prostaglandin metabolites with the various stages of developing bone by utilizing the matrix-induced endochondral bone formation system. During mesenchymal cell proliferation a peak of endogenous thromboxane B₂ was detected. In the subsequent stages of chondrogenesis and chondrolysis PGF₂α was in high concentration, whereas during bone formation PGE₂, 6-Keto-PGF₁α and thromboxane B₂ were elevated. These changes in the peak levels of the various prostaglandin metabolites may reflect differences in the cell populations and function associated with various stages of endochondral bone formation.