TABLE 4

Log EC50 values for the rate of SPAP secretion between 5 and 6 h after the addition of agonists

The agonists were incubated with the cells for 10 min to 5 h, the agonists were washed out, and the cells were incubated for the remaining time in serum-free media for up to a total of 5 h of incubation. SPAP secretion between 5 and 6 h was then measured. Values represent means ± S.E.M. of n determinations. For isoprenaline and salbutamol, the log EC50 values for the two components are shown and the percentage that represented the higher potency site 1 in each case. Only one component was seen with salmeterol and CGP 12177 as agonists.

Log EC50 Site 1 Log EC50 Site 2 % Site 1 n
Two-Component Fit Isoprenaline
5 h −8.45 ± 0.19 100 7
2 h −8.34 ± 0.15 −4.99 ± 0.34 81.3 ± 3.0 7
1 h −8.51 ± 0.17 −5.65 ± 0.17 50.8 ± 2.5 9
30 min −8.25 ± 0.23 −5.56 ± 0.09 26.6 ± 3.2 10
10 min −6.00 ± 0.12 0 7
Salbutamol
5 h −8.60 ± 0.06 100 7
2 h −8.46 ± 0.04 −5.02 ± 0.29 72.8 ± 5.7 5
1 h −8.57 ± 0.14 −5.82 ± 0.28 41.2 ± 3.8 6
30 min −8.67 ± 0.25 −5.81 ± 0.30 17.1 ± 2.8 3
10 min −5.83 ± 0.26 0 7
One-Component Fit Log EC50
Salmeterol
5 h −10.74 ± 0.16 3
2 h −10.61 ± 0.31 3
1 h −10.53 ± 0.19 3
30 min −10.43 ± 0.18 3
10 min −10.10 ± 0.13 3
CGP 12177
5 h −9.51 ± 0.14 7
2 h −8.28 ± 0.18 4
1 h −9.43 ± 0.09 6
30 min −9.28 ± 0.03 6
10 min −8.85 ± 0.09 6