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Table 1 IC50 values and inhibition constants (Ki) for ketoconazole and xenoestrogens on CYP1A- and CYP3A activities assayed in vitro.

From: Interactions between xenoestrogens and ketoconazole on hepatic CYP1A and CYP3A, in juvenile Atlantic cod (Gadus morhua)

Compound(s)

IC50(μM)1,a

Ki(μM)1,a

IC50(μM)2,b

Ki(μM)2,b

IC50(μM)3,b

Ketoconazole (KC)

0.6 (0.0)c

0.04 – low [S]

0.3 (0.1)c

0.2

0.4c

  

0.2 – high [S]

   

Nonylphenol (NP)

5.2 (1.1)

3.5

160 (40)

Not analysed

35

Ethynylestradiol

20 (1.2)

5.4 – low [S]

40 (7.1)

54 – low [S]

50

  

10.3 – high [S]

 

95 – high [S]

 

KC:NP (1:5)

1.3 (0.2):6.2 (1.0)

Not analysed

5.3 (1.1):25.0 (5.3)

Not analysed

Not analysed

  1. 1 Hepatic Microsomal CYP1A activity; 2 Hepatic Microsomal CYP3A activity; 3 cDNA Expressed Human CYP3A4; a Substrate [S] = 7-Ethoxyresorufin; b [S] = 7-Benzyloxy-4-[trifluoromethyl]-coumarin; c Published in [22]. Each IC50 value represents the mean from 2–4 separate assays, followed by the SD, in brackets. The Ki values are estimated from one representative Dixon plot.