Plasma estradiol,free testosterone,sex hormone binding globulin binding capacity,and prolactin in benign prostatic hyperplasia and prostatic cancer

The nature of hormonal changes with age and the possible role of these changes in the development of benign prostatic hyperplasia (BPH) and prostatic cancer (PC) were studied by assaying the plasma levels of total and free testosterone (T), estradiol (E₂), prolactin, and sex hormone binding globulin binding capacity (SHBG) in 20 normal healthy men aged 40-59 years, in 30 patients with BPH aged 63-79 years, and in 30 patients with PC of similar height, weight, and age as the BPH patients. The mean E₂ was highly significantly (P < 0.0005) lower in the PC patients and in the young controls than in the BPH patients. The mean free T was significantly higher in the young controls than in the BPH patients (P < 0.025) and PC patients (P < 0.0005). The PC patients had a slightly lower (P < 0.05) mean free T and mean E₂/free T ratio than the BPH patients. The mean E₂/free T ratio was significantly higher in the BPH patients (P < 0.0005) and in the PC patients (P < 0.0025) than in the young controls. It seems possible that the observed age-dependent significant increase in plasma estrogen concentration in the BPH patients may act as a protective factor against prostatic cancer.