Probenicid inhibition of fluorescence extrusion after MCB-staining of rat-1 fibroblasts
✍ Scribed by Martin Poot; Francesca N. Hudson; Angelika Grossmann; Peter S. Rabinovitch; Terrance J. Kavanagh
- Book ID
- 101241409
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 318 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0196-4763
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✦ Synopsis
The intracellular fluorescence level of cells stained continuously with monochlorobimane was monitored by flow cytometry in order to assess the initial rate of glutatione to monochlorobimane conjugation as a measure of glutathione S-transferase activity. In addition to a rapid initial increase and a plateau level, a decline in fluorescence intensity was found upon prolonged flow cytometric monitoring. Exposure to probenicid, an inhibitor of an ATP-dependent organic anion pump, prevented this decrease. Incubation with vanadate and verapamil was without effect. Thus, extrusion of fluorescent-glutathione-conjugate perturbs the proportionality between initial glutathione level and monochlorobimane-dependent fluorescence intensity. Monitoring by flow cytometry the decrease in monochlorobimane-dependent fluorescence may be useful to detect multidrug resistant cells.