A simple radioimmunoassay for the measurement of testosterone glucosiduronate in unextracted urine.

A simple, reliable and rapid radioimmunoassay (RIA) for the determination of testosterone glucosiduronate (TG) in crude urine is described. Two protein-TG complexes were investigated in raising antibodies: a) Bovine serum albumin (BSA)-TG and b) human plasma Cohn's fraction IV-4 (CF)-TG. In rabbits, high titers of antibodies were obtained after the injection of CF-TG. The specificity of the antiserum was sufficiently high (cross reaction with free testosterone 27%, with 5alpha-dihydrotestosterone-glucosiduronate 20%). TG was estimated in small aliquots of male and female urine after evaporation overnight at 50 degrees C in order to eliminate interfering material. The intraassay coefficient of variation (CV) was found to be 6% and the interassay CV 11%. TB has been determined in 40 samples of urine simultaneously by "direct" RIA and by a "classical" RIA following hydrolysis with beta-glucuronidase. The coefficient of correlation was found to be 0.89. The mean excretion of TG in the urine of 26 healthy men amounted to 164+/-51 mug/24 hours with a range from 97 to 346 mug/24 hours. In a group of 16 women a mean urinary excretion of TG of 24+/-10 mug/24 hours was determined. The method allows a technician to assay 40 samples per day.