Cytoplasmic estradiol binding sites in testis of fertile and infertile men.

Free cytoplasmic estradiol receptor was determined in testicular biopsies from six adults showing various primary testicular disorders, and in testicular tissue obtained at autopsy from 18 males of various ages. Estradiol receptors were found in all cases examined. Receptor concentration varied during testicular maturation and from one patient to another. The presence of the receptor at an early stage of development and the changes observed in its concentration during testicular maturation and dysfunction support the idea that estradiol may play, through its receptor interaction, an important role in the regulation of testicular steroidogenesis during postnatal human development.