Steroid-sensitive proteins, growth hormone and somatomedin C in prostatic cancer: Effects of parenteral and oral estrogen therapy

The effects of parenteral and parenteral plus oral estrogen therapy on the serum levels of sex hormone binding globulin (SHBG), pregnancy‐associated (α‐PAG), growth hormone (GH), and somatomedin C (SmC) were studied in 26 patients with prostatic cancer. Intramuscular polyestradiol phosphate treatment, yielding a mean serum level of estradiol‐17β of 1,446 pM and a mean testosterone level of 4.5 nM, had no significant effects on α‐PAG, GH, and SmC and increased SHBG levels only marginally. Combined treatment with intramuscular polyestradiol phosphate and oral ethinyl estradiol greatly increased SHBG and α‐PAG levels and caused elevated GH and decreased SmC levels. The route of estrogen administration is probably of major importance for the hormonal effects on hepatic activity as reflected by SHBG and α2‐PAG levels. Bypassing the portal circulation might be advantageous with respect to liver‐related side effects of estrogen therapy. GH and SmC might act as mediators of estrogen effects on the human liver.