The Effect of Calcium Concentration on Calcium Uptake by Bone Cells Treated with Thyrocalcitonin (TCT) Hormone

Abstract

The effect of calcium concentration and thyrocalcitonin (TCT) on the uptake of calcium by bone cells in vitrowas studied. Both TCT and elevated calcium concentrations caused an accumulation of calcium in the cells. Given in conjunction, the effect of the two was larger than the separate effects added together. The amount of radiocalcium released by the cells during incubation was inversely related to the amount of calcium accumulated in the cells. The findings can be explained by assuming two types of calcium fluxes between medium and cells: a) a concentration dependent influx, and b) a constant rate calcium extrusion process subject to TCT inhibition. (Endocrinology92: 550O, 1973)