EFFECTS OF ANGIOTENSIN-II ON BONE-CELLS IN-VITRO

Other than its known effects on the cardiovascular system, angiotensin II (Ang II) stimulates cell growth in several cell types. In this stu dy, we examined whether it also might affect bone cell metabolism. Ang II stimulated DNA and collagen synthesis and decreased alkaline phosp hatase (AP) activity in bone cell populations derived from the periost eum of fetal rat calvariae. Similar effects of Ang II were observed on human adult bone cells obtained by collagenase digestion from trabecu lar bone. Clonal cell analysis, autoradiographic studies, and receptor subtype analysis suggested the presence of specific Ang II receptor s ubtype 1 (AT(1)) binding sites on AP(+) osteoblastic precursor cells. Ang II had no direct effects on osteoblastic cells with a mature pheno type, but paracrine effects of Ang II on mature osteoblasts could be o bserved upon coculture with Ang Ii-responsive bone cell populations. B ecause Ang II is known to be locally generated by endothelial cells, A ng II might play an important role in coordinating capillary cell grow th and osteoblastic bone formation during bone remodeling. (C) 1998 Wi ley-Liss, Inc.