Skip to main content
HHS Logo U.S. Department of Health & Human Services Divider arrow NIH logo National Institutes of Health Alt desc
Toxicology in the 21st Century

Tox21 Assays

The following table lists the Tox21 assays currently available at NCATS. Review additional details about these assays.

Assay

Assay End Point*

Cell Type

Assay Readout

Cell viability
Apoptosis

Intracellular ATP,
Caspase-3/7

Hek293, Jurkat, HepG2, Sh-SY5Y, SK-N-SH, BJ, HUV-EC-C, MRC-5, mesangial, kidney
proximal tubules, N2a, H-4-II-E, NIH3T3

Luminescence

Membrane integrity

LDH release,
Protease release

HEK293, mesangial

Fluorescence,
Luminescence

Mitochondrial toxicity

Membrane potential

HepG2

Fluorescence

DNA damage

Micronucleus

CHO

Fluorescence

Cytokine

IL-8, TNF-α

THP-1

Homogenous
time-resolved fluorescence

Nuclear receptor

AR, ERα, FXR, PPARδ, PPARγ, RXR, TRβ, VDR, GR, hPXR, AhR, rPXR, CAR, ERR

Hek293, HeLa, HepG2

β-Lactamase reporter,
Luciferase reporter

Toxicity pathway

AP-1, HIF-1α, SIE, NF-κB, HSR, ESRE, ARE/Nrf2, CREB, p53, real-time cytotoxicity and viability

ME-180,HeLa, HepG2, Hek293, CHO, HCT-116, HepG2

β-Lactamase reporter,
Luciferase reporter

hERG channel

Thallium influx

U-2OS

Fluorescence

G-protein-coupled receptor signaling TRHR, TSHR Hek293 Fluorescence, Homogeneous time-resolved fluorescence
Enzyme activity AChE SH-SY5Y Fluorescence
Developmental pathway Retinol signaling, Hedgehog/Gli, SBE/Smad C3H10T1/2, 3T3, HEK 293T Luciferase reporter, Fluorescence

*AChE, acetylcholinesterase; AhR, aryl hydrocarbon receptor; AP-1, activator protein-1; AR, androgen receptor; ARE/Nrf2, antioxidant response element/NF-E2 related factor 2; CAR, constitutive androstane receptor; CREB, cAMP response element binding; ERα, estrogen receptor α; ERR, estrogen-related receptor; ESRE, endoplasmic reticulum stress response element; FXR, farnesoid X receptor; GR, glucocorticoid receptor; HIF-1α, hypoxia-inducible factor-1α; hPXR, human pregnane X receptor; HSR, heat shock response element; IL-8, interleukin-8; LDH, lactate dehydrogenase; NF-κB, nuclear factor kappa B; PPARδ, peroxisome proliferator-activated receptor δ; PPARγ, peroxisome proliferator-activated receptor γ; rPXR, rat pregnane X receptor; RXR, retinoid X receptor; SBE/Smad, Smad binding element; SIE, sis-inducible element; TNF-α, tumor necrosis factor α; TRβ, thyroid hormone receptor β; TRHR, thyrotropin-releasing hormone receptor; TSHR, thyroid-stimulating hormone receptor; VDR, vitamin D receptor.