Table 2

Sulfonylurea affinities and potencies in recombinant and native KATP channels

ha SUR1/KIR6.20.72 nM  (0.94)0.13 nM  (1.23)17 nM  (0.94)3.8 nM  (1.26)6.9 μM  (0.93)1.2 μM  (1.26)29 μM  (0.98)4.9 μM  (1.30)
pancreatic β cells1.4 nM  (0.96)a 0.05 nM  (1.51)b 21 nM  (0.96)4.0 nM  (n.d.)c 7.8 μM  (0.97)0.5 μM  (1.30)c 32 μM  (0.93)d 2.5 μM  (1.53)e
rat SUR2B/KIR6.2250 nM  (0.96)42 nM  (1.27)6.1 μM  (0.99)1.2 μM  (1.32)9.2 μM  (0.93)1.6 μM  (1.26)260 μM  (1.02)88 μM  (1.29)
aortic rings (rat)430 nM  (1.12)f 97 nM  (1.20)f 6.3 μM  (1.00)f 1.5 μM  (1.25)f n.d.n.d.n.d.n.d.
  • Dissociation constants (K Ds) for hamster SUR1 or rat SUR2B and EC50 values to inhibit activity of recombinant channels were taken from Figs. 1 and 2. K Ds for binding of glipizide and meglitinide to pancreatic β cells were assessed in a membrane fraction from mouse pancreatic islets using a [3H]glibenclamide displacement assay (see Experimental Procedures). The other data are from: a Schwanstecher et al., 1991; b Gromada et al., 1995; c Zünkler et al., 1988; d Schwanstecher et al., 1992b; e Gillis et al., 1989; f Quast et al., 1993. EC50 values to inhibit β cell K ATP channel activity were measured using the cell-attached (e) or the whole-cell configuration (b, c) of the patch-clamp technique. Data for intact aortic rings were assessed using [3H]P1075 displacement and inhibition of86Rb+ efflux (f). n.d. = not determined.