[In vitro culture of neonatal mouse calvaria as a model for study of bone resorption]

We established the in vitro culture system of neonatal mouse calvaria. Bone resorption was determined by the following examinations; (1) the release of calcium from the calvaria into the medium was measured by use of atomic absorption spectrophotometer, and the treated to control ratio was calculated and used as an index of bone resorption; (2) the concentration of osteocalcin in the cultured medium was determined by radioimmunoassay; (3) histological examination. By combined use of the examinations, we were able to objectively determine the bone resorption of cultured calvaria.