Table 10.

Reversible interaction of GSK1562590 (10 nM) binding at rat, monkey and human recombinant UT

UT cell membrane	[125I]hU-II Bmax at washout t= 0 (% vehicle)	Time for [125I]hU-II Bmax >90% vehicle
Rat UT (n= 2)	5.2–38.3%	>1 h
Monkey UT (n= 4)	92.5 ± 5.2%	0 h
Human UT (n= 2)	38.5–61.2%	<1 h

All values are expressed as mean ± SEM, where n represents the number of individual experiments performed in duplicate. UT membranes were incubated with DMSO or 10 nM GSK1562590 for 30 min at 25°C following which the incubation mixtures were diluted, centrifuged and resuspended in buffer. Following resuspension, [¹²⁵I]hU-II K_D and B_max values were determined (t= 0). A subset of membranes were ‘washed’ a second time at various times following the initial resuspension (t= 0.5, 1 or 2 h) to assess GSK1562590 binding reversibility (time for [¹²⁵I]hU-II B_max >90% vehicle). K_D and B_max values were determined by homologous competition binding whereby multiple concentrations of unlabelled hU-II were used to compete for binding with a fixed concentration of [¹²⁵I]hU-II (Douglas et al., 2005). GSK1562590 did not alter the K_D values for [¹²⁵I]hU-II for any of the three UT orthologues studied.