The calcium-sensing receptor is antagonised by MK-5442 and triggers a short burst of PTH secretion. Binding of PTH to its receptor enhances osteoblast functions and bone formation. The presence of the Wnt antagonists Dkk-1 and sclerostin inhibit Wnt signalling. Dkk-1 needs to form a complex with kremen, whereas sclerostin binds LRP5/6 directly. BHQ-880 and AMG-785 are antibodies directed against Dkk-1 and sclerostin, respectively. After neutralising Dkk-1 and sclerostin, Wnt can bind to LRP5/6, which results in the degradation GSK-3β. As a consequence, β-catenin is stabilised, accumulates, and translocates into the nucleus where it regulates the transcription of osteoblastic genes. Abbreviations used: APC, adenomatosis polyposis coli; cAMP, cyclic adenosine monophosphate; CaSR, calcium sensing receptor; Dkk-1, dickkopf-1, GSK, glycogen synthase kinase 3; LRP, low-density lipoprotein receptor-related protein; PKA, protein kinase A; PTH, parathyroid hormone; PTH1R, PTH 1 receptor.