Acute effects of interferon-alpha administration on testosterone concentrations in healthy men

Recombinant human interferon alpha (rhIFN-alpha) is used therapeutically in malignant disorders and chronic hepatitis. The present study was assessed to study the effects of rhIFN-alpha on the hypothalamic-pituitary-testicular (HPT) axis. We performed a saline-controlled cross-over study in six healthy men, sequentially measuring the serum concentrations of gonadotropins, testosterone, the free androgen index (FAI) and sex hormone-binding globulin (SHBG) after a bolus subcutaneous injection of rhIFN-alpha. rhIFN-alpha induced a sustained decrease of both testosterone (from 19.5+/-1.88 to a nadir of 5.49+/-0.51nmol/l at the end of the study) and FAI (from 98.7+/-14.7 to a nadir of 32. 1+/-5.3 at the end of the study), whereas concentrations of LH, FSH and SHBG were not different between the two studies. Our results suggest that rhIFN-alpha affects the HPT axis at the testicular level, either directly or indirectly, and changes feedback relationships between the pituitary and the testis