[Effects of Rifampicin and Streptomycin on the Concentrations of Testosterone and Cortisol in the Blood of Men (author's Transl)]

It has been shown previously that the biosynthesis and metabolism of oestrogens is affected by rifampicin. The present study was undertaken to investigate if rifampicin may also influence the plasma concentrations of testosterone and cortisol. Five male patients suffering from tuberculosis received rifampicin or streptomycin. During treatment with rifampicin testosterone concentrations were significantly elevated as compared to control conditions; this increase was found in the morning (8.00 h) as well as in the afternoon (16.30 h). When the same patients were treated with streptomycin, only irregular changes of testosterone concentrations were observed. The blood level of cortisol was increased in two patients, but unchanged in three patients who were treated with rifampicin. No changes at all were detected in patients under treatment with streptomycin. The results presented here show that rifampicin -- in contrast to streptomycin -- influences the biosynthesis of testosterone and possibly also that of cortisol.