TABLE 1

Agonist potencies (EC50) and maximal responses (Rmax) for calcitonin secretion, IP1 accumulation and intracellular calcium response in 6-23 cells.

Potencies are in μM for all assays. Rmax levels are in pg/ml for the calcitonin assay and nM for the IP1 assay and have been normalized to Δfluorescence units of 10 mM [Ca2+]e in the intracellular calcium assay.

Assay[Ca2+]e[Sr2+]e
Rmax ± S.E.M.EC50 (pEC50± S.E.M.)Rmax ± S.E.M.EC50 (pEC50 ± S.E.M.)
Calcitonin313 ± 202440 (2.61 ± 0.13)304 ± 24794 (3.10 ± 0.13)
IP1858 ± 1504810 (2.32 ± 0.01)787 ± 468320 (2.08 ± 0.01)
Intracellular calcium100 ± 3.501470 (2.83 ± 0.09)44.3 ± 1.183050 (2.52 ± 0.05)