Sardine procalcitonin amino-terminal cleavage peptide has a different action from calcitonin and promotes osteoblastic activity in the scales of goldfish

Comp Biochem Physiol A Mol Integr Physiol. 2017 Sep;211:77-83. doi: 10.1016/j.cbpa.2017.06.007. Epub 2017 Jun 11.


The nucleotide sequence of a sardine preprocalcitonin precursor has been determined from their ultimobranchial glands in the present study. From our analysis of this sequence, we found that sardine procalcitonin was composed of procalcitonin amino-terminal cleavage peptide (N-proCT) (53 amino acids), CT (32 amino acids), and procalcitonin carboxyl-terminal cleavage peptide (C-proCT) (18 amino acids). As compared with C-proCT, N-proCT has been highly conserved among teleosts, reptiles, and birds, which suggests that N-proCT has some bioactivities. Therefore, both sardine N-proCT and sardine CT were synthesized, and their bioactivities for osteoblasts and osteoclasts were examined using our assay system with goldfish scales that consisted of osteoblasts and osteoclasts. As a result, sardine N-proCT (10-7M) activated osteoblastic marker enzyme activity, while sardine CT did not change. On the other hand, sardine CT (10-9 to 10-7M) suppressed osteoclastic marker enzyme activity, although sardine N-proCT did not influence enzyme activity. Furthermore, the mRNA expressions of osteoblastic markers such as type 1 collagen and osteocalcin were also promoted by sardine N-proCT (10-7M) treatment; however, sardine CT did not influence their expressions. The osteoblastic effects of N-proCT lack agreement. In the present study, we can evaluate exactly the action for osteoblasts because our scale assay system is very sensitive and it is a co-culture system for osteoblasts and osteoclasts with calcified bone matrix. Both CT and N-proCT seem to influence osteoblasts and osteoclasts and promote bone formation by different actions in teleosts.

Keywords: Calcitonin; Japanese sardine; Osteoblasts; Osteoclasts; Procalcitonin amino-terminal cleavage peptide; Scales.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Calcitonin / analogs & derivatives*
  • Calcitonin / genetics
  • Calcitonin / pharmacology*
  • Goldfish
  • Osteoblasts / drug effects*
  • Phylogeny
  • Sequence Homology, Amino Acid


  • calcitonin, sardine
  • Calcitonin