Plasma sex hormone binding globulin in patients with prostatic carcinoma.

The concentrations of sex hormone binding globulin (SHBG) were measured in the plasma of 56 men, who were 47 to 85 years of age, by time-resolved immunofluorometric assay with a monoclonal antibody. Twenty-five of the men had untreated carcinoma of the prostate and 17 had untreated prostatic hyperplasia. There were 14 healthy control subjects. SHBG levels were significantly higher in patients with prostatic carcinoma (37.6 +/- 8.4 nmol/l) than in those with prostatic hyperplasia (24.5 +/- 5.2 nmol/l; P less than 0.05) or control subjects (14.9 +/- 2.8 nmol/l; P less than 0.01). It is not known why SHBG levels are higher in patients with carcinoma or hyperplasia of the prostate. The contradictory results obtained in other studies may be due to heterogeneity of the binding globulin causing its values to vary in the different assays used.