PARATHYROID-HORMONE EFFECT ON CELL-TO-CELL COMMUNICATION IN STROMAL AND OSTEOBLASTIC CELLS

We characterized the formation and regulation of the gap junction in c alvarial osteoblasts and in a series of subtypes from marrow stromal c ells. The stromal cells included osteogenic, chondro-osteogenic, and e ndothelial cells. The cell coupling was measured by using fluorescence dye injected into single cells, and its migration to neighboring cell s was measured. The functional coupling of cells was highly expressed by the osteoblastic cells. This process is mediated through fast chang es in intracellular Ca+2 levels. Calcium ionophore (A 23187) demonstra ted an uncoupling effect on the cells. In addition, the exposure of th e cells to the parathyroid hormone increased the formation of the gap junction complex; the highest level was demonstrated in the osteoblast ic cells. (C) 1998 Wiley-Liss, Inc.