Pregnane X Receptor (PXR; NR1I2)
| Product Family | Product Number | Product Description | Technical Manual |
| IB0700 PXR (NR1I2) |
IB07001-32 | Human PXR Reporter Assay System, 3 x 32 assays in 96-well format | Technical Manual |
| IB07001 | Human PXR Reporter Assay System, 1 x 96-well format assays | Technical Manual | |
| IB07002 | Human PXR Reporter Assay System, 1 x 384-well format assays | Technical Manual |
Pregnane X Receptor Assay Kit 
This Pregnane X Receptor (PXR) assay kit is an all-inclusive PXR reporter assay system that includes, in addition to PXR Reporter Cells, two optimized media for use during cell culture and in diluting the user’s test samples, a reference agonist, Luciferase Detection Reagent, and a cell culture-ready assay plate. PXR Reporter Cells cannot be refrozen or maintained in extended culture.
PXR Reporter Cells are prepared using INDIGO’s proprietary CryoMite™ process. This cryo-preservation method yields exceptional cell viability post-thaw, and provides the convenience of immediately dispensing healthy, division-competent reporter cells into assay plates. There is no need for cumbersome intermediate treatment steps such as spin-and-rinse of cells, viability determinations, or cell titer adjustments prior to assay setup.
INDIGO’s PXR reporter assay kits feature a luciferase detection reagent specially formulated to provide stable light emission between 5 and 90+ minutes after initiating the luciferase reaction. Incorporating a 5-minute reaction-rest period ensures that light emission profiles attain maximal stability, thereby allowing assay plates to be processed in batch. By doing so, the signal output from all sample wells, from one plate to the next, may be directly compared within an experimental set.
INDIGO's PXR assay kits are offered in different assay formats to accommodate researchers’ needs: 3x 32, 1x 96, and 1x 384 assay formats for screening small numbers of test compounds, as well as custom bulk reagents for HTS applications.
Bulk assay reagents can be custom manufactured to accommodate any scale of HTS. Please inquire.
PXR assay kits also available in: Rat, Mouse, Cynomolgus Monkey, Dog
Pregnane X Receptor Assay Services
The primary application of INDIGO’s cell-based nuclear receptor assays are to quantitatively assess the bioactivity of a test compound as an agonist (activator) or antagonist (inhibition of an agonist response) of a given receptor. Service assays include a positive control reference compound and “vehicle” control for every experiment. A formal study report and all data files are provided to the client upon completion of the study. To receive a quote for your proposed study, complete & submit the online “Request a Quote” form or contact an INDIGO Customer Service Representative to discuss your desired study parameters.
PXR Service Assays: Human, Rat, Mouse, Cynomolgus Monkey, Dog
Pregnane X Receptor Background
Pregnane X Receptor is a nuclear receptor that binds and is activated by variety of endogenous and xenobiotic compounds. Activated by the antibiotic rifampicin and various plant metabolites, such as hyperforin, guggulipid, colupulone, and isoflavones, PXR's response to specific ligands is species-specific. It is activated by naturally occurring steroids, such as pregnenolone and progesterone, and binds to a response element in the promoters of the CYP3A4 and ABCB1/MDR1 genes.
INDIGO's Pregnane X Receptor (PXR) reporter assay utilizes proprietary mammalian cells engineered to provide constitutive, high-level expression of the Human Pregnane X Receptor (NR1I2), a ligand-dependent transcription factor commonly referred to as PXR. PXR is also known as the Steroid and Xenobiotic sensing nuclear receptor (SXR).
INDIGO’s Reporter Cells express a hybrid form of human PXR. The N-terminal sequence encoding the PXR DNA binding domain (DBD) has been substituted with that of the yeast GAL4-DBD. The native PXR ligand binding domain (LBD) and other C-terminal domains remain intact and functional. Ligand interaction activates the receptor, causing it to binds to the GAL4 DNA binding sequence, which is functionally linked to a resident luciferase reporter gene. Thus, quantifying changes in luciferase activity in the treated reporter cells provides a sensitive surrogate measure of the changes in PXR activity. The principle application of this reporter assay system is in the screening of test samples to quantify any functional activity, either agonist or antagonist, that they may exert against human PXR.
For more information on PXR, visit the Nuclear Receptor Resource.
Synonyms: Pregnane X Receptor, PXR, Human Pregnane X Receptor, Human PXR, hPXR, NR1I2
Pregnane X Receptor Assay Data
Agonist dose-response analyses of Human PXR. Performance of the human PXR assay using the reference agonists Rifampicin (provided), Hyperforin dicyclohexylammonium (Enzo Life Sciences), TO901317(Cayman Chemical), SR12813 (Tocris), and Mevastatin (Cayman Chemical). Luminescence was quantified and average relative light units (RLU) and corresponding standard deviation (SD) values were determined for each treatment concentration (n = 4). Fold-activation and Z’ values were calculated as described by Zhang, et al. (1999). Non-linear regression and EC50 analyses were performed using GraphPad Prism software. High Z' scores confirm the robust performance of this assay, and its suitability for HTS.
Pregnane X Receptor Assay Research Areas
Xenobiotic Metabolism; Bile Acid and Xenobiotic; NASH/NAFLD; Drug-Nutrient Interaction