AMYLIN STIMULATES OSTEOBLAST PROLIFERATION AND INCREASES MINERALIZED BONE VOLUME IN ADULT MICE

Amylin, a 37-amino-acid peptide co-secreted with insulin from the beta -cells of the pancreatic islets, has previously been demonstrated to i nhibit bone resorption in vitro. However, its effects on bone formatio n and bone mass have not been assessed. We report that periphysiologic al concentrations of amylin stimulate proliferation of fetal rat osteo blasts in vitro. When amylin is injected daily for 5 days over the cal variae of adult mice in vivo, there are substantial increases in histo morphometric indices of bone formation, a reduction in bone resorption , and a significant increase in mineralized bone area; Equimolar doses of calcitonin in this in vivo model produced an inhibition of bone re sorption but no significant effect on bone area. These findings suppor t a role for amylin as a physiological regulator of bone and suggest t hat it should also be evaluated as a potential treatment for osteoporo sis. (C) 1995 Academic Press, Inc.