Table 3.
Palosuran lacks high affinity for native hUT receptor endogenously expressed in the rhabdomyosarcoma cell line SJRH30: radioligand-binding affinity constants (Ki values, [125I]hU-II competition) for human urotensin-II (hU-II), palosuran and SB-657510 at the native hUT receptor in whole cell preparations following 1 and 4 h incubation periods
| Ki (nM) |
Relative affinitya |
||||
|---|---|---|---|---|---|
| 1 h incubation | 4 h incubation | Ratio | 1 h incubation | 4 h incubation | |
| Urotensin-II | 0.2±0.0 | 0.3±0.1 | 1.5 | 0.1 | 0.2 |
| SB-657510 | 56.9±9.7 | 213.0±71.2 | 3.7 | 0.9 | 3.5 |
| Palosuran | 49.8±3.3 | 192.5±57.2 | 3.9 | 9.8 | 37.7 |
Abbreviation: hUT, human urotensin-II receptor.
a
Relative affinity is expressed as the native human UT Ki relative to the corresponding value obtained in recombinant hUT membrane preparations (see Table 1). All values are expressed as mean±s.e.m. Statistical comparisons were made using an unpaired, two-tailed t-test and no values were determined from 1 h (n=3).