- STAT3 activation in stromal/osteoblastic cells is required for induction of the receptor activator of NF-kappaB ligand and stimulation of osteoclastogenesis by gp130-utilizing cytokines or interleukin-1 but not 1,25-dihydroxyvitamin D3 or parathyroid hormone. O'Brien, C.A., Gubrij, I., Lin, S.C., Saylors, R.L., Manolagas, S.C. J. Biol. Chem. (1999)