Effects of calcitonin gene-related peptide and amylin on human osteoblast-like cells proliferation

Expression of mRNA for calcitonin gene-related peptide (CGRP) and CGRP rece ptor has been detected in osteoblasts indicating that CGRP could play a rol e in bone metabolism. In the present study, we evaluated the effect of CGRP on primary culture of human osteoblast-like cells proliferation. The pepti de was able to stimulate [H-3]thymidine incorporation in human osteoblast-l ike cells with a maximal effect at 10(-8) M. The proliferating activity of CGRP was not inhibited by the two antagonists, CGRP-(8-37) or amylin-(8-37) , whereas amylin fragment antagonized the proliferating activity of amylin. In human osteoblast-like cells CGRP, but not amylin, was able to stimulate adenylyl cyclase activity and this effect was completely antagonized only by CGRP-(8-37) and not by amylin-(8-37). These data suggest that the CGRP i nduced stimulation of cAMP is not involved in the peptide proliferating eff ect in human osteoblast-like cells and that in this cell population there a re receptor subtypes for CGRP, distinct from that of amylin. (C) 2000 Elsev ier Science B.V. All rights reserved.