− Taurine is the most abundant amino acid in many tissues and is found to be enhancing the bone tissue formation or inhibits the bone loss. Although it is reported that taurine reduces the alveolar bone loss through inhibiting the bone resorption, its functions of taurine and expression of taurine transporter (TauT) in bone have not been identified yet. The purpose of this study is to clarify the uptake mechanism of taurine in osteoblast using mouse osteoblast cell lines. In this study, mouse stromal ST2 cells and mouse osteoblast-like MC3T3-E1 cells as osteoblast cell lines were used. The activity of taurine uptake was assessed by measuring the uptake of ]taurine uptake in ST2 cells treated with 4 mM calcium was increased by 1.7-fold of the control which was a significant change. In contrast, in Ca ++ -free condition and L-type calcium channel blockers (CCBs), taurine transport to osteocyte was significantly inhibited. In oxidative stress conditions, [ 3 H]taurine uptake was decreased by TNF-α and H 2 O 2 . Under the hyperosmotic conditions, taurine uptake was increased, but inhibited by CCBs in hyperosmotic condition. These results suggest that, in mouse osteoblast cell lines, taurine uptake by TauT was increased by the presence of extracellular calcium, whereas decreased by CCBs and oxidative stresses, such as TNF-α and H 2 O 2 .

− Imbalance in calcium and phosphorous metabolism due to aging or menopause leads to osteoporosis. In contrast to patients with normal blood pressure, hypertensive patients have a higher loss of calcium in the urine with its attendant risk of osteoporosis. The high blood pressure is associated with the risk of bone loss and abnormalities in calcium metabolism leading to calcium loss. So we retrospectively investigated the changes of bone mineral density (BMD) which drugs can have clinical influences over osteoporosis treatments of patients with calcium-antagonists as common antihypertensive drugs and with bisphosphonates which causes a most effective inhibition of osteoclasts resorption. As a result over 70 years of age group and within bisphosphonates group, alendronate 70 mg once-weekly group showed significant increase of BMD in lumbar area. Combination group of cilnidipine and maxmarvil ® showed very significant decrease of BMD. In conclusion, it is desirable that combination therapy with calcium-antagonists is used carefully in the treatment of osteoporosis with high blood pressure.