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

Objective: Recombinant human interferon alpha (rhIFN-alpha) is used therape utically in malignant disorders and chronic hepatitis. The present study wa s assessed to study the effects of rhIFN-alpha on the hypo thalamic-pituita ry-testicular (HPT) axis. Design and methods: We performed a saline-controlled cross-over study in si x healthy men, sequentially measuring the serum concentrations of gonadotro pins, testosterone, the free androgen index (FAI) and sex hormone-binding g lobulin (SHBG) after a bolus subcutaneous injection of rhIFN-alpha. Results: rhIFN-alpha induced a sustained decrease of both testosterone (fro m 19.5 +/- 1.88 to a nadir of 5.49 +/- 0.51 nmol/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 s tudy), whereas concentrations of LH, FSH and SHBG were not different betwee n the two studies. Conclusions: Our results suggest that rhlFN-alpha affects the HPT axis at t he testicular level, either directly or indirectly and changes feedback rel ationships between the pituitary and the testis.