Effects of Vitamin D Metabolites on Mineralization of Embryonic Chick Femurs In Vitro

Abstract

We examined the effects of vitamin D metabolites on mineralization of the 10-day embryonic chick femurs in organ culture system. When 5-day cultures kept in the control medium were cultured in the several mediums containing 1α (OH) D₃, 1, 25 (OH) ₂D₃ or 24, 25 (OH) ₂D₃ at concentration of 10^-11-10^-8 M during an additional 5 days, the mineralization of cultured bones increased in the treatment with 1α (OH) D₃ at concentration of 10^-10-10^-8M, and decreased in the treatment with 1, 25 (OH) ₂D₃ at concentration of 10^-10-10^-8 M, and was no change in the treatment with 24, 25 (OH) ₂D₃. The activities of both alkaline phosphatase and acid phosphatase did not change in the cultured bones with vitamin D metabolites. These results suggested that 1α (OH) D₃ increased bone formation, 1, 25 (OH) ₂D₃ stimulated bone resorption, and 24, 25 (OH) ₂D₃ had no effect to bone-remodeling in this organ culture system.