Terbium fluorescence studies of cisplatin binding to GH3/B6 pituitary tumor cells.
Terbium (Tb3+) fluorescence was used to investigate the interaction of cisplatin with GH3/B6 pituitary tumor cells. The binding of cisplatin to GH3/B6 cells quenched the fluorescence intensity of bound Tb3+. The IC50 for cisplatin inhibition of Tb3+-GH3/B6 fluorescence was determined to be 190 microM. Cisplatin was found to non-competitively inhibit the cellular binding of Tb3+, causing a dramatic decrease in the maximum number of high-affinity Tb3+ binding sites (by 33%), without markedly affecting their binding affinity. The half-life for the cellular binding of cisplatin was calculated to be 2.7 min. It was suggested that the plasma membrane of GH3/B6 cells contain a specific protein receptor for binding cisplatin.
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D000818:Animals; D002460:Cell Line; D002945:Cisplatin / Q000378:metabolism* / Q000494:pharmacology; D006207:Half-Life; D007700:Kinetics; D010911:Pituitary Neoplasms / Q000378:metabolism*; D051381:Rats; D013050:Spectrometry, Fluorescence; D013725:Terbium / Q000378:metabolism
D013725:Terbium; D002945:Cisplatin