Table 2

PXR orthologs from different species are activated by structurally diverse xenobiotics and steroids

5β-pregnane-3,20-dione, 10 μM++++
RU486, 10 μM+++
PCN, 10 μM++++
RIF, 100 μM++++
Clotrimazole, 10 μM+++

Agonist profiles for each receptor were determined by cotransfection of expression vectors for mouse (Kliewer et al., 1998; Lehmann et al., 1998), rat (Savas et al., 1999), rabbit (Savas et al., 1999), or human (Bertilsson et al., 1998; Blumberg et al., 1998; Lehmann et al., 1998) PXR with either a DR-3 or ER-6 reporter construct. Because different reporter constructs and different cell lines were used in these transfection assays, only qualitative descriptions are used to compare the responses: strong activator, ++; modest activator, +; and not efficacious, –.