A micromethod for the measurement of estrogen receptors using high pressure liquid chromatography

Adequate sample size has been one of the difficulties encountered in routine determination of estrogen receptors in prostatic disease. The recent commercial availability of protein analysis columns for use with high pressure liquid chromatography (HPLC) equipment has made the achievement of a considerable reduction in sample size feasible. We present a method for determination of ER which includes the use of 16 alpha-125-iodo-estradiol ( [125I]-E2) of 1600 Ci/mmol specific activity, the use of G-25 column chromatography, followed by fractionation by HPLC and finally relation of the fmol specifically bound to mg protein measured in the HPLC peak. Data obtained upon determination of ER in the immature rat uterine model system are given to show consistent recoveries, ligand specificity, saturability, inhibition, and commonly accepted KD and n values for this system. Also, in a pilot study on 13 samples from human prostatectomies, the utility of the HPLC technique for ER measurement in that tissue using single point analysis is demonstrated. For comparison, all receptor determinations reported were also made using conventional methods.