Parathyroid hormone and other agents that stimulate bone resorption function, at least in
part, by inducing osteoblasts to secrete cytokines that stimulate osteoclast differentiation and
activity. We previously demonstrated that parathyroid hormone induces expression by
osteoblasts of interleukin-6 and leukemia inhibitory factor without affecting the 16 other
cytokines that were examined. We also showed that stimulation of osteoclast activity by
parathyroid hormone is dependent on activation of the cAMP signal transduction pathway …