[Free testosterone index: comparison with plasma free testosterone].

Blood-free testosterone indices were measured among 28 normal men (age; 24-48 yrs.), 20 normal women (20-36 yrs.), 18 pregnant women (22-31 yrs.), 17 males with hypogonadism (23-56 yrs.), 17 males with chronic hepatitis (20-42 yrs.), 24 males with liver cirrhosis (29-68 yrs.), 34 males with hyperthyroidism (20-42 yrs.) and 7 hirsute women (18-31 yrs.), and these were compared with the plasma concentrations of free testosterone. The testosterone index was obtained by multiplying the plasma concentration of testosterone by the percent of sex hormone-binding globulin (SHBG), non-bound testosterone precipitated by dextran-coated charcoal. A significant increase of plasma testosterone was observed in patients with chronic hepatitis (p less than 0.001) and hyperthyroidism (p less than 0.001) as compared with normal men and was also observed in pregnant (p less than 0.01) and hirsute women (p less than 0.01) as compared with normal women. The close negative correlation between plasma levels of testosterone and the percent of SHBG non-bound testosterone (r = -0.87, n = 79, p less than 0.001) was observed among normal men, male patients with chronic hepatitis and hyperthyroidism. The sex hormone binding capacity was increased from two to three fold in patients with chronic hepatitis and hyperthyroidism. The patients with compensated liver cirrhosis had increased plasma testosterone and a decreased percent of SHBG non-bound testosterone, and those with decompensated liver cirrhosis had decreased plasma testosterone and a normal percent of SHBG non-bound testosterone. The plasma concentration of free testosterone was normal in patients with chronic hepatitis and hyperthyroidism. It decreased in pregnancy (p less than 0.01) and increased in hirsute women (p less than 0.01). The blood free testosterone index was slightly high in one third of the patients with chronic hepatitis and hyperthyroidism as compared with that in normal men. However, a close correlation of the percent of SHBG non-bound testosterone and fractional free testosterone (%) measured by equilibrium dialysis (gamma = 0.82, p less than 0.001) was obtained in all subjects (n = 170). These data suggest that the blood free testosterone index parallels the plasma concentration of free testosterone and is useful to evaluate the status of androgenicity.