SYSTEMIC ADMINISTRATION OF AMYLIN INCREASES BONE MASS, LINEAR GROWTH,AND ADIPOSITY IN ADULT MALE-MICE

Amylin is a peptide hormone cosecreted with insulin from the pancreati c p-cells that can act as an osteoblast mitogen and as an inhibitor of bone resorption. The effects on bone of its systemic administration a re uncertain. The present study addresses this question in adult male mice that were given daily subcutaneous injections of amylin (10.5 pg) or vehicle (n = 20 in each group) for 4 wk. Histomorphometric indices of bone formation increased 30-100% in the amylin-treated group, wher eas resorption indices were reduced by similar to 70% (P < 0.005 for a ll indices). Total bone volume in the proximal tibia was 13.5 +/- 1.4% in control animals and 23.0 +/- 2.0% in those receiving amylin (P = 0 .0005). Cortical width, tibial growth plate width, tibial length, body weight, and fat mass were all increased in the amylin-treated group. It is concluded that systemic administration of amylin increases skele tal mass and Linear bone growth. This peptide has potential as a thera py for osteoporosis if its bone effects can be dissociated from those on soft tissue mass.