Testosterone concentrations and sirolimus in male renal transplant patients

Sirolimus damages the testes in animals; however, human data are sparse. We conducted a case-control study to obtain further insight into this issue and compared testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin concentrations in matched renal transplant patients who did or did not receive sirolimus. We found that testosterone values were lower (11.2 +/- 6.3 nmol/L vs. 15.5 +/- 7.7 nmol/L, p < 0.05), in 28 sirolimus-treated patients, compared to 28 non-sirolimus-treated controls. Furthermore, these patients more commonly had testosterone concentrations that were below our reference value for normal men. In contrast, FSH and LH concentrations were higher while prolactin levels were not different. These data are consistent with sirolimus-related testosterone suppression and suggest a need for further studies.