The procalcitonin amino-terminal cleavage peptide (N-proCT) lacks biological activity on normal clonal rat osteoblastic and preosteoblastic cells in vitro.

The human-derived procalcitonin amino-terminal cleavage peptide, N-proCT has previously been shown to act mitogenically on isolated chicken and human osteoblast-like cells and on the human osteosarcoma cell line U-2 OS. We have examined the effect of N-proCT on growth and phenotype of cloned rat osteoblastic and preosteoblastic cells. Neither cell growth nor the phenotype (ALP, PTH response) of either cell type was significantly changed by the procalcitonin cleavage peptide.