- Tumor necrosis factor alpha inhibits the stimulatory effect of the parathyroid hormone-related protein on cyclic AMP formation in osteoblast-like cells via protein kinase C+. Blind, E., Knappe, V., Raue, F., Pfeilschifter, J., Ziegler, R. Biochem. Biophys. Res. Commun. (1992)