By using a fluorescent ligand for a retinoid X receptor (RXR), said ligand being indicated by one of the following formulas (1)-(3), an evaluative test of ability to bind with RXR can be easily performed. (In the formulas, R1 is methyl, alkoxy, or styryl, R2 is hydroxy, alkoxy, or alkylamino, A is N or CH, B is NH or O, R3 is isopropyl or tertiary butyl, and R4 is isopropyl or isobutyl).本發明係關於使用下列式(1)至式(3)中之任一者所示之視網酸X受體之螢光配體能夠容易地進行對視網酸X受體結合能力之檢測。其中式(1)至式(3)中,R1為甲基、烷氧基或苯乙烯基;R2為羥基、烷氧基或烷基胺基;A為N或CH;B為NH或O;R3為異丙基或第三丁基;R4為異丙基或異丁基。
