Osteoblast(OBL) cells were isolated from ICR Swiss neonatal mouse calvarial tissues and cultured in a CO2 incubator with minimum essential medium (MEM) containing 0.25g BSA. The cells were cultured for 7 days and were treated with bovine parathyroid hormone (bPTH, 1-34) and calcitonin(CT). Enzyme activities related to mineral metabolism and other biochemical actions within the bone cells including protein phosphorylation were investigated. In other experiments using cultured calvarial bone tissues, hormones were treated for 24, 48, 72 or 96 hours. The activities of $eta$-glucuronidase enzymes involved in bone collagen synthesis and mineral deposits were increased by 8% with bPTH and were inhibited with CT treatment, while those were 67% increase treated with bPTH and CT together. On the other hand, alkaline phophatase(AP) activities were inhibited by PTH hormone at all the time courses observed. Protein phosphorylation reaction in OBL was mediated by bPTH, cAMP and ionized Ca. Phosphorylation was observed in different cell fractions including homogenate, membrane and cytosol. The number of proteins phosphorylated by PTH, cAMP, and Ca were 10, 5, and 9, respectively. Most of the protein kinases(PKs) were existed in cytosolic compartment. In membrane fractions, two bPTH-dependent-PKs (70K, 50K Da) were observed of which 70K Da protein was also Ca-dependent. Most of the cAMP-dependent PKs were regulated via bPTH. 70K, 50K, 5K, 19K, 16K, 10.5K phosphoproteins regulated by Ca share the same pathways as those by bPTH-dependent proteins. Ca seems to regulate PK activities differently from cAMP.