EN
The presence and location of specific binding sites for progesterone and 17β-estradiol in cells of wheat were estimated using radioligand binding assay. Membrane and cytosolic fractions of non-vernalized and vernalized plants were tested using tritium-labelled ligands. Specific binding of [3H]progesterone and [3H]17β-estradiol occurs in wheat cells. The binding sites are located in membranes and in the cytosol. Specific binding of [3H]17β-estradiol is higher in the membranes than in the cytosol. Specific binding of both ligands in the cytosolic fraction is higher in vernalized plants than in non-vernalized ones. The possibility of the occurrence of steroid binding proteins specific for progesterone and 17β-estradiol, putative steroid receptors for these steroids in Triticum aestivum L., is discussed.