Angiotensin II stimulates the proliferation of osteoblast-rich populations of cells from rat calvariae.

We examined the effects of angiotensin II (Ang II) on the proliferation of osteoblast-rich populations of cells obtained from calvariae of newborn rat. Addition of Ang II to the culture medium caused dose-dependent increases in the rate of DNA synthesis. Such increases were completely inhibited by the addition of DuP753, an antagonist of AT1 receptor. Ang II potentiated the production of inositol 1,4,5-trisphosphate (IP3) in the culture. Ang II also stimulated the activities of mitogen-activated protein kinases (MAPKs) upon binding to the AT1 receptor. These results suggest that Ang II might be intimately involved in the proliferation of the cells in calvariae through the AT1 receptor.