The chemokine interleukin-8 regulates parathyroid secretion.

Interleukin-8 (IL-8) is a chemokine important in inflammatory processes. Homology cloning experiments performed using bovine parathyroid cDNA and degenerate primers encoding transmembrane regions III and VI of peptide and protein hormone G-protein coupled receptors identified a set of known receptors not previously identified in the parathyroid. Among these was the IL-8 type B receptor. Incubation of freshly isolated bovine parathyroid cells with recombinant IL-8 for 6-48 h produced an increase in the levels of mRNA for parathyroid hormone (PTH). The levels of PTH secreted in response to nanomolar amounts of IL-8 were also elevated in cells incubated for 1 h with IL-8. Differential display analysis of mRNA from parathyroid cells, incubated in the presence and absence of IL-8, permitted the identification of cDNA clones for RNA species whose expression was either elevated or suppressed. These experiments suggest that IL-8 and inflammatory events play a role in bone homeostasis through actions on the parathyroid gland.