Simultaneous Occurrence of Individual Estrogen- and Androgen Receptors in Female and Male Target Organs

Reserachers at the Max-Planck-Institut fur Zellbiologie in Wilhelmshaven Germany studied possible relationships between estradiol receptors and dihydrotestosterone receptors in uteri seminal vesicles and prostates. Tissues were removed from 12-week-old calves and 6-month-old castrated male pigs. The dihydrotestosterone receptor remained in solution while the estradiol receptor was removed from target organ extracts by absorption to the coupling product of (4-diazobenzyl) cellulose andestradiol in 2- or 4- position. The 2 receptors are individual but concomitant in the target organs of both sexes. On the other hand a 1000-fold excess of estradiol completely inhibited the binding of dihydrotestosterone to its receptor. A 1000-fold excess of dihydrotestosterone resulted in a 42% reduction of receptor-bound estradiol. Thus although the receptors are individual a cross-affinity also exists. With physiological concentrations the cross-affinity may be of only negligible importance. The beneficial effects of high estrogen doses to prostate cancer patients may be due to competitive inhibition of androgens.