Table 1.

Summary of IC₅₀s, K_i, and relative potencies determined for beluga and mouse AHRs.

HAH	Chlorination pattern	Beluga				Mouse
		Mean IC50	Mean Ki	95% confidence interval for Ki	Relative potency (from mean Ki)	Mean IC50 (nM)	Mean Ki (nM)	95% confidence interval for Ki	Relative potency (from mean Ki)
TCDD	2,3,7,8	0.47	0.10	0.05–0.22	1.00	1.21	0.36	0.25–0.51	1.00
TCDF	2,3,7,8	1.35	0.33	0.24–0.46	0.31	1.62	1.1	0.21–5.8	0.32
126	3,3′,4,4′,5	8.1	1.6	1.3–2.1	0.063	12.6	4.6	3.1–6.8	0.078
169	3,3′,4,4′,5,5′	25.1	7.5	3.9–14.7	0.014	63.1	33	8.3–132	0.011
77	3,3′,4,4′	35.5	7.8	7.3–8.3	0.013	224	94	47.6–185	0.0038
81	3,4,4′,5	89.1	19	12.9–26.8	0.0055	112	34	30–38	0.011
105	2,3,3′,4,4′	3550	567	292–1100	0.00018	5010	1620	927–2830	0.00022
118	2,3′,4,4′,5	6310	1440	930–2220	0.000071	6310	3190	930–10900	0.00011
156	2,3,3′,4,4′,5	1590	309	196–485	0.00033	1000	284	186–433	0.0013
128	2,2′,3,3′,4,4′	2240	384	246–600	0.00027	6310	1420	826–2450	0.00025

^aMean IC₅₀ was determined from the two experiments conducted at 2 nM [³H]TCDD (nominal concentration; measured concentration was 1.6 nM for both experiments).

^bMean K_i was determined from all three data sets, including two experiments at 2 nM [³H]TCDD (1.6 nM measured) and one experiment at 1 nM [³H]TCDD (0.9 nM measured). The 95% confidence intervals for K_i values were calculated from the mean and SD of all three experiments.