Table 3.

cAMP Responses in UMR106/GloSensor cells^a

	EC50 (nM)		EMax (%)		Washout AUC (%)
		p		p		p
PTH(1‐34)	0.20 ± 0.03	1.000	100 ± 0.4	1.00	100 ± 0	1.00
PTHrP(1‐36)	0.46 ± 0.11	0.062	88.4 ± 2.8	0.007	92 ± 11	0.530
M‐PTH/PTHrP	0.72 ± 0.13	0.012	96.2 ± 2.4	0.143	700 ± 85	< 0.0001
LA‐PTH	0.12 ± 0.01	0.020	94.7 ± 2.9	0.105	763 ± 135	0.001

Responses at each ligand concentration were calculated as the area‐under‐the‐curve (AUC) values obtained from the time‐course plots of cAMP‐dependent luminescence versus time measured over 30 min, and then expressed as a percent of the maximum AUC response observed for PTH(1‐34) in each assay, the average of which was 3.13 ± 0.66 × 10−6 counts per second (cps) • min; the corresponding minimum value (not subtracted) was 3.58 ± 2.16 × 10−8 cps • min. Washout values report the AUC of the cAMP‐dependent luminescence versus time measured for each ligand at a near EC50‐concentration over 90 min and expressed as a percent of the response observed for PTH(1‐34) (0.3 nM) in each assay, the average of which was 0.96 ± 0.87 × 10−6 cps • min; and the corresponding value in vehicle‐treated cells (not subtracted) was 0.48 ± 0.1×10−6 cps • min. Data are means ± SEM of six experiments, with duplicate wells in each; p = Student's t test versus PTH(1‐34).

^acAMP responses were measured in rat osteoblastic UMR‐106/GloSensor (UGS‐56) cells. EC50 values are peptide concentrations (nM) that stimulated 50% of the maximum response (EMax) observed for that peptide.