Dramatic suppression of plasma and urinary prostate specific antigen and human glandular kallikrein by antiandrogens in male-to-female transsexuals

Purpose: Prostate specific antigen (PSA) and human glandular kallikrein (hK 2) are mainly produced by the prostate and their genes are regulated by and rogens through the androgen receptor. We determine whether PSA and hK2 chan ge significantly in plasma and urine after antiandrogen treatment in male-t o-female transsexuals. Materials and Methods: Plasma and urine PSA and hK2 were measured with high ly sensitive immunofluorometric procedures capable of detecting within 1 or 6 ng./l. PSA or hK2, respectively. Study groups consisted of 10 men treate d with cyproterone acetate only (group 1), 15 transdermal estradiol plus cy proterone acetate (group 2) and 31 ethinyl estradiol plus cyproterone aceta te (group 3). Plasma and urine samples were collected before initiation of treatment as well as after 4 months of hormonal therapy. For a subset of gr oup 3 patients blood and urine samples were also obtained after 12 months o f treatment. Results: Cyproterone acetate, a steroidal antiandrogen, alone or with estra diol was able to suppress greater than 90% of plasma and urinary PSA and hK 2 concentration after 4 or 12 months of therapy. Conclusions: Cyproterone acetate therapy causes dramatic suppression of pla sma and urinary PSA and hK2 in men without prostate cancer. Since cyprotero ne acetate is used for prostate cancer treatment, suppression of PSA after hormonal therapy may not accurately reflect therapy success in reducing tum or burden.