Table 1

Activation of human and zebrafish PXRs by androstane and estrane steroids

Cmp. #
Compound
hPXR Activity
hPXR Efficacy
zfPXR Activity
zfPXR Efficacy
Toxicity


ANDROSTANES





AN1
5α-Androstan-3α,17β-diol
5.38
0.68
5.19
0.84
None
AN2
5α-Androstan-3,17-dione (androstanedione)
4.90
0.87
5.50
0.86
None
AN3
5α-Androstan-3α-ol (androstanol)
5.20
0.5
5.34
1.00
None
AN4
5α-Androstan-3α-ol-17-one (androsterone)
4.73
0.93
5.60
0.87
None
AN5
5α-Androstan-17β-ol-3-one (dihydrotestosterone)
4.94
0.39
5.21
0.59
None
AN6
5β-Androstan-3α-ol-17-one (etiocholanolone)
5.24
0.54
5.47
0.88
200
AN7
4-Androsten-3,17-dione (androstenedione)
4.69
0.59
5.44
0.14
None
AN8
4-Androsten-17β-ol-3-one (testosterone)
4.14
0.22
5.61
0.12
None
AN9
5-Androsten-3β-ol-17-one (DHEA)
4.49
0.52
4.89
0.35
None
AN10
5α-Androst-16-en-3α-ol (androstenol)
5.26
0.7
5.44
1.02
None
AN11
5β-Androstan-3α,11β-diol-17-one
4.72
0.51
4.52
1.04
None
AN12
5-Androsten-3β-sulfate-17-one (DHEA sulfate)
4.32
0.22
None

None
AN13
5β-Androstan-3α-ol-17-one (epiandrosterone)
5.31
0.7
5.02
0.43
None
AN14
5β-Androstan-3α-ol-11,17-dione
4.39
0.15
5.01
0.49
None
AN15
4-Androsten-17α-ol-3-one (epitestosterone)
4.17
0.9
None

None
AN16
4-Androsten-17α-glucosiduronate-3-one (epitestosterone glucuronide)
4.86
0.69
None

None
AN17
4-Androsten-17α-sulfate-3-one (epitestosterone sulfate)
5.47
0.67
None

None
AN18
5β-Androstan-3α-glucosiduronate-17-one (etiocholanolone glucuronide)
None

None

None
AN19
5α-Androstane
None

None

100
AN20
5α-Androstan-3β-ol
6.10
0.43
5.57
1.66
50
AN21
5α-Androst-16-en-3β-ol
5.32
1.01
5.48
2.11
50
AN22
5α-Androst-16-en-3-one
5.52
0.96
5.58
0.68
100
AN23
5β-Androstan-3α-ol
5.85
1.12
5.59
0.33
None
AN24
Androst-4,16-dien-3-one
5.15
0.64
5.96
0.17
100
AN25
Androst-5,16-dien-3β-ol
None

5.60
1.50
100








ESTRANES












ES1
1,3,5(10)-Estratrien-3,17β-diol (estradiol)
4.80
0.34
None

200
ES2
1,3,5(10)-Estratrien-3-ol-17-one (estrone)
4.42
0.47
None

200
ES3
1,3,5(10)-Estratrien-3,16α,17β-triol (estriol)
None

None

200
ES4
1,3,5(10)-Estratrien-3,16α-diol-17-one (16α-hydroxyestrone)
5.60
0.42
5.70
0.17
None
ES5
1,3,5(10)-Estratrien-3-ol-4-methoxy-17-one (4-methoxyestrone)
5.40
0.93
5.62
0.19
None
ES6
1,3,5(10)-Estratrien-3,15α,16α,17β-tetrol (estetrol)
5.67
0.29
None

200
ES7
1,3,5(10)-Estratrien-2,3-diol-17-one (2-hydroxyestrone)
5.44
0.93
5.74
0.19
None
ES8
1,3,5(10)-Estratrien-17-one-3-sulfate (estrone sulfate)
5.47
0.43
None

None
ES9
1,3,5(10)-Estratrien-17β-ol-3-glucosiduronate (estradiol glucuronide)
None

None

None
ES10
1,3,5(10)-Estratrien-17β-ol-3-sulfate (estradiol sulfate)
6.05
0.6
None

200
ES11
1,3,5(10)-Estratrien-17α-ethinyl-3,17β-diol (ethinyl estradiol)
5.72
0.68
None

200

Activities are in -log(EC50), with EC50 in molar units for the activation of human or zebrafish PXR. Efficacy is relative to 10 μM rifampicin (human PXR) or 20 μM 5α-androstan-3α-ol (zebrafish PXR) which are assigned an efficacy of 1.0. Toxicity is the lowest concentration in micromolar that produced significant toxicity in the HepG2 cells.

Ekins et al. BMC Evolutionary Biology 2008 8:103   doi:10.1186/1471-2148-8-103