ANDROGEN INTERACTION WITH THE ESTROGEN-RECEPTOR IN HUMAN-TISSUES

The influence of different androgens upon the binding of 17β-oestradiol to its cytoplasmic receptor has been investigated in human endometrium. Under equilibrium binding conditions testosterone, 5α-dihydrotestosterone, androstenedione, dehydroepiandrosterone, 5α-androstane 3β, 17βdiol, androst-5-ene-3β, 17βdiol do not compete with 17β-oestradiol for the oestrogen binding sites up to a 100 fold molar excess. 5α-androstane-3β, 17βdiol and androst-5-ene-3β, 17βdiol, however, inhibit competitively the initial rate of formation of the 17β-oestradiol-receptor complexes in a concentration-dependent manner. The other androgens do not elicit the same effect. Biological implications of these observations were investigated in a human breast cancer line, MCF-7, in long term tissue culture.10-7M of both androst-5-ene-3β,17βdiol and 5α-androstane 3β,17βdiol translocates the oestrogen receptor and stimulates thymidine kinase activity and progesterone receptor production of these cells, two responses considered specifically oestrogenic. © 1979.