The changes in the binding capacity of testosterone-oestradiol binding globulin (TeBG) following castration and DES-D administration in patients with prostatic carcinoma.

The levels of plasma testosterone, testosterone-oestradiol binding globulin (TeBG) and total serum acid phosphatase (TSAP) following antiandrogenic hormone therapy were investigated in 17 patients with prostatic carcinoma. The low levels of plasma total and free testosterone induced by castration decreased further after diethylstilboestrol diphosphate (DES-D) administration. Plasma TeBG binding capacity after castration was 118.9% of the pre-treatment level and increased to 193.9%, 204.0% and 212.7% at 1, 2 and 3 weeks after DES-D dosing. The in vitro binding of 3H-testosterone to TeBG was not influenced in the presence of DES-D or stilboestrol. Clinical response following the DES-D therapy was associated with a decrease in the levels of TSAP. A significantly inversed correlation was found between the decrease in TSAP and increase in TeBG at completion of DES-D therapy. These results suggest that the high binding capacity of TeBG lowers the biologically active fraction of testosterone and thus may produce clinical effects.