- Parathyroid hormone (PTH) and PTH-like protein (PLP) stimulate interleukin-6 production by osteogenic cells: a possible role of interleukin-6 in osteoclastogenesis. Löwik, C.W., van der Pluijm, G., Bloys, H., Hoekman, K., Bijvoet, O.L., Aarden, L.A., Papapoulos, S.E. Biochem. Biophys. Res. Commun. (1989)