Radioligand purification prior to routine receptor assays.
The need to repurify the commercially available radioligands [3H]estradiol and [3H]testosterone before use in routine assays was investigated. Storage of these products for 2 months after delivery led to appreciable degradation of [3H]estradiol compared to [3H]testosterone. Unexpectedly, TLC and even HPLC procedures were ineffective in completely restoring the purity of [3H]-estradiol and the unremoved polar products induced important variations in our estrogen receptor assays. An increase in non-specific binding and a comcomitant decrease in total binding were observed resulting in an underestimation of specific binding sites and of the affinity constant. In some cases Scatchard analysis was not possible. We therefore strongly recommend the repurification of low-stability radioligands and propose an economic time-saving procedure for the purification of [3H]estradiol by solvent differential partition which requires no high-cost investment in apparatus.
Le Goff
J M
JM
Laboratoire de Cancérologie, Faculté de Médecine Nord, CNRS UA 1175, Marseille, France.
Berthois
Y
Y
Martin
P M
PM
D001943:Breast Neoplasms; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D003600:Cytosol / Q000378:metabolism; D004355:Drug Stability; D004958:Estradiol / Q000302:isolation & purification* / Q000378:metabolism; D006801:Humans; D011869:Radioligand Assay; D011960:Receptors, Estrogen / Q000378:metabolism; D012996:Solutions; D013739:Testosterone / Q000302:isolation & purification* / Q000378:metabolism; D014316:Tritium; D014407:Tumor Cells, Cultured
D011960:Receptors, Estrogen; D012996:Solutions; D014316:Tritium; D013739:Testosterone; D004958:Estradiol