Effects of parathyroid hormone, calcitonin, and dibutyryl‐cyclic AMP on osteoclast area in cultured chick tibia

Slices of osteoclast-enriched endosteal surfaces of 3 week chick tibia were cultured for 1-3 days. Osteoclasts on the bone surface were made visible by acridine orange fluorescence. Osteoclast area was measured by image analysis. Parathyroid hormone (PTH) caused osteoclasts to increase in area about 40%, and calcitonin (CT) caused a decrease in area also of about 40%. Subsequent addition of dibutyryl cyclic AMP to PTH- or to CT-treated cells...