OBJECTIVE: 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. DESIGN AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
EP Corssmit, E Endert, HP Sauerwein and JA Romijn
SW van Thiel, JA Romijn, NR Biermasz, BE Ballieux, M Frolich, JW Smit, EP Corssmit, F Roelfsema and AM Pereira
OBJECTIVE: Recently a new depot preparation of the long-acting somatostatin analogue, lanreotide Autogel was introduced for the treatment of acromegaly. Like octreotide long-acting repeatable (LAR), it has high binding affinity for the somatostatin receptor subtype SSTR 2 and less binding affinity for SSTR 5. We hypothesized that the ability to suppress growth hormone (GH) secretion in patients with acromegaly would be similar for these depot preparations. PATIENTS AND STUDY DESIGN: Seven patients (mean age+/-S.E.M. 48.4+/-7 years) on long-term octreotide LAR treatment at a monthly injection interval for a mean of 2.8 years were enrolled in the study. They underwent a GH secretory profile study with 10 min sampling for 24 h, 28 days after an injection. At 2, 4 and 6 weeks after the next injection fasting GH profiles (every 30 min for 3.5 h) and serum IGF-I measurements were measured. These investigations were repeated 12 months later, when the patients were on an individually titrated stable dose of lanreotide Autogel. RESULTS: Secretory characteristics and total 24 h GH secretion, estimated by deconvolution analysis of the 10 min 24 h plasma GH concentrations, did not show differences between these two long-acting somatostatin analogues. Both drugs were equally effective in GH and IGF-I suppression as measured at 2, 4 and also at 6 weeks following an injection. CONCLUSION: The efficacy of lanreotide Autogel and octreotide LAR was equal, notwithstanding that these drugs are administered in a different way and have different pharmacokinetics.