Effect of diethylstilbestrol on plasma testosterone levels during 24 hours: study comparing doses of 1 and 5 mg. daily, and 1 mg. 3 times daily.

A study was done on 30 patients with advanced adenocarcinoma of the prostate treated with diethylstilbestrol. Three groups of patients were given daily doses of 1, 5, and 1 times 3 mg. diethylstilbestrol, respectively. The study was confined to the effects of treatment on the levels of plasma testosterone by taking hormonal specimens every 4 hours for 24 hours. The results showed little difference of plasma testosterone among the groups under study and a statistical analysis showed no significant differences. Therefore, our study showed no appreciable advantage in the dosage spread over the day, compared to commonly used doses of 1 or 5 mg. diethylstilbestrol given in a single dosage.