In-Vitro Toxicology Glutathione S-Transferases and High Throughput Screening

GSTs - sensitive biomarkers of organ damage and in-vitro toxicology

Glutathione S-transferases are found in high concentrations in several organs of key toxicological importance, such as the kidney and liver. They are rapidly and readily released in the event of toxicological insult making them very sensitive biomarkers of organ damage. GSTs are clinically proven biomarkers of renal and hepatic injury. GSTs can increase the value obtained from in-vitro toxicology studies as follows:

In-Vitro Prediction of Pre-Clinical Toxicity.

As part of a testing algorithm, alpha GST enables preclinical hepatotoxicity to be predicted from in-vitro hepatocyte cultures(1). GST release is a sensitive biomarker of increased cellular permeability which, when combined with biomarkers of cell growth (cell number) and mitochondrial function (ATP and MTT),provides an estimate of toxicity that is close to that found in vivo plus providing information as to the mechanism of toxicity. This can greatly speed the elimination of potentially toxic compounds from HTS programmes reducing costs and freeing up resources for more promising candidates. By performing in-vivo toxicity testing early in the evaluation of HTS hits, information can be provided to the combinatorial chemists to guide the development of future compounds.

In - Vitro Models of Hepatic and Renal Toxicity.

Hepatic and renal tubular cells can be grown in-vitro and probed with new chemical entities. If the substance is toxic the cells will release alpha GST into the culture medium making the combination of in-vitro culture and alpha GST release a very sensitive model for detecting toxicological potential.

Variety of Experimental Models.

GSTs can be used to test for toxicity using cell culture, tissue slices(2) or perfused whole organs. The cellular specificity of GSTs enables the response of different cell types in the organ to be studied independently. For example, in human kidney slices, the proximal and distal tubular cells can be monitored independently(3).

Matching In-vivo and In-vitro Models.

Matching assays are available for in-vitro studies and in-vivo studies in rat/mouse and human/primate models making it possible to use the same biomarkers throughout the development process.

Consistency Throughout the Development Process. Biotrin has assays available for in-vitro, rat/mouse and primate/human GSTs.

Easy Automation

The Biotrin GST EIA kits are 96 well Microtiter EIA kits capable of easy automation(4).

For further information on the use of the Biotrin GST EIAs and how they could be used in your studies, please contact Martin Shaw at Biotrin (martin.shaw@biotrin.ie) who will be happy to offer any help that he can.

The following are Biotrin's range of kits for use in high throughput screening and other in-vitro models of toxicology:

• Biotrin High Sensitivity Alpha GST EIA Biotrin PiGST EIA
• Biotrin Urinary Alpha GST EIA
• Biotrin Rat Alpha GST EIA
• Biotrin Rat GSTYb1 EIA

1. McKim, J.M. Jr., et al. (2001). A new approach to in vitro toxicity screening based on multi-endpoint analysis provides information on mechanisms and predicts in-vivo toxicity. Poster presented at the 40th Annual Meeting of the Society of Toxicology, San Francisco, March 25-29, 2001.
   
2. Vickers, A.E.M. (1994). Use of human organ slices to evaluate the biotransformation and drug-induced side-effects of pharmaceuticals. Cell Biology and Toxicology; 10: 407-414.
   
3. Data on file at Biotrin International.
   
4. Wilga, P.C. et al. (2001). Characterization of the rat alpha-glutathione-transferase (GST) ELISATM (Biotrin) using rat hepatoma (H4IIE) Cells. Poster presented at the 40th Annual Meeting of the Society of Toxicology, San Francisco, March 25-29, 2001.