TABLE 1.
Ki values for inhibition of Na,K-ATPase isoforms α1β1 and α2β1 with selectivity ratios (Kiα1/Kiα2)
Amines used were as follows. DOH, hydroxylamine; DGly, glycine; DGlMe, glycine methyl ester; DGlyN, glycinamide; DAlaN, alaninamide; DSer, serine; DSerN, serinamide; DSCar, semicarbazide; DPrN, propionamide; DEtDA, ethylene diamine; DMe, methylamine; DEt, ethylamine; DMeCF3, trifluorethylamine; DbisGly, glycine; Dbis, digoxigenin bis-digitoxoside. p values were calculated by Student's t test and denoted as follows: *, p < 0.05; **, p < 0.01; ***, p < 0.001. n, number of independent experiments. p (α2vα1), significance of differences between Kiα2β1 and Kiα1β1. p (v digoxin), significance of the difference of the selectivity ratio (Kiα1β1/Kiα2β1) compared with the (Kiα1β1/Kiα2β1) of digoxin.
| CG (identifying number) | Ki − α1β1 ±S.E. | Ki − α2β1 ±S.E. p (α2 v α1), n | Kiα1β1/Kiα2β1 ±S.E. p (v digoxin) |
|---|---|---|---|
| nm | nm | ||
| Ouabain | 97 ± 4.3 | 90 ± 14 | 1.08 ± 0.17 |
| Digoxigenin | 139 ± 17 | 130 ± 5.5 | 1.07 ± 0.17 |
| Digoxin | 189 ± 11 | 55 ± 4.4*** (12) | 3.44 ± 0.34 |
| DOH (1) | 311 ± 18.5 | 134 ± 35* (3) | 2.32 ± 0.62 |
| DGly (2) | 124 ± 8.6 | 25 ± 3.9*** (6) | 5.1 ± 0.54* |
| DGlMe (3) | 540 ± 102 | 128 ± 11* (3) | 4.22 ± 0.88 |
| DGlyN (4) | 152 ± 5.5 | 20.4 ± 1*** (8) | 7.45 ± 0.46*** |
| DAlaN (5) | 232 ± 28 | 67 ± 8.1** (3) | 3.46 ± 0.59 |
| DSer (6) | 316 ± 109 | 145 ± 28.5 (3) | 2.18 ± 0.86 |
| DSerN (7) | 242 ± 15 | 144 ± 3.5* (3) | 1.68 ± 0.13 |
| DSCar (8) | 102 ± 23 | 20 ± 3.6* (4) | 4.98 ± 1.2* |
| DPrN (9) | 249 ± 37 | 47 ± 7.8** (3) | 5.28 ± 0.75* |
| DEtDA (10) | 69 ± 10 | 16.7 ± 2.1** (3) | 4.10 ± 0.82 |
| DMe (11) | 101 ± 4.4 | 15.6 ± 2.3*** (8) | 6.47 ± 0.71*** |
| DEt (12) | 53 ± 3.4 | 18.5 ± 4.9** (5) | 2.88 ± 0.78 |
| DMeCF3 (13) | 199 ± 33 | 44 ± 7* (3) | 4.50 ± 1.0 |
| Dbis | 196 ± 8.5 | 74 ± 5** (3) | 2.65 ± 0.81 |
| DbisGly (14) | 80 ± 5.5 | 34.9 ± 12 (3) | 2.29 ± 0.80 |