Mr. Hall et al., SURFACE BINDING AND CLEARANCE OF CALCITONIN BY AVIAN OSTEOCLASTS, Comparative biochemistry and physiology. Part A, Physiology, 108(1), 1994, pp. 59-63
Osteoclasts, isolated from chick tibias and maintained in culture for
4-6 days, were treated with biotinylated calcitonin followed by fluore
scent avidin. In 2 min the entire cell surface fluoresced, by 7.5 min
fluorescence was centrally clustered and by 10 min fluorescence had di
minished to background levels. Specific binding was blocked by excess
unlabeled calcitonin and not influenced by unrelated peptide, The resu
lts show that avian osteoclasts bind calcitonin specifically and that
the bound calcitonin is rapidly cleared from the cell surface, which i
ndicates involvement of receptor-mediated endocytosis.