Type I estrogen receptors cannot be histochemically localized in frozen tissue sections using estradiol-albumin-FITC conjugates.

Only few investigators still report in literature that estradiol type I receptors can be histochemically visualized using estradiol-albumin-FITC conjugates (E2-BSA-FITC). Most of them report that it is not likely that fluorescence is due to conjugate--type I receptor interaction. It is assumed that rather type II receptors are involved. In this study clear evidence is presented that type I receptors are not visualized. There is some indication that specific staining is only obtained when type II binding sites are present.