Serum hormone concentrations during treatment with multiple rising doses of recombinant follicle stimulating hormone (Puregon) in men with hypogonadotropic hypogonadism

Objective: To study increases of serum FSH and gonadal response in gonadotropin-deficient men treated with recombinant FSH (Puregon; NV Organon, Oss, The Netherlands). Design: An open, prospective, multiple rising dose study in which volunteers received single daily IM doses of recombinant FSH for 3 weeks. The dose administered was increased at weekly intervals: the first 7 days, 75 IU/d; the subsequent 7 days, 150 IU/d; and the last 7 days, 225 IU/d. Participants: Nine men suffering from isolated gonadotropin deficiency or panhypopituitarism. Main Outcome Measurements: Immunoreactive FSH, LH, inhibin, T, and androstenedione. Results: Serum immunoreactive FSH (median) rose in accordance with the recombinant FSH doses administered from 0.5 mIU/mL (range <0.05 to 1.9 mIU/mL) at baseline to 4.3 mIU/mL (range 2.0 to 8.5 mIU/mL), 8.4 mIU/mL (range 4.9 to 17.8 mIU/mL), and 13.6 mIU/mL (5.6 to 28.4 mIU/mL) after 1, 2, and 3 weeks of medication, respectively. The elimination half-life of recombinant FSH was 48 +/- 5 hours (mean +/- SD), which was slightly longer than that reported after single dose administration of recombinant FSH (32 +/- 12 hours). The bioactivity of recombinant FSH was reflected by serum inhibin levels, which rose from 116 U/L (range 34 to 356 U/L) at baseline to 350 U/L (range 63 to 1,109 U/L) at day 22. However, serum FSH and inhibin levels did not cor relate when compared after 1, 2, and 3 weeks of recombinant FSH administration. Serum immunoreactive LH, T, androstenedione, and E(2) were 0.2 mIU/mL (range <0.05 to 0.7 mIU/mL [conversion factor to SI unit, 1.0]), 58 ng/dL (range <12 to 222 ng/dL [conversion factor to SI unit, 0.0347]), 14 ng/dL (range 6 to 115 ng/dL [conversion factor to SI unit, 0.0349]), and 14 pg/mL (range <14 to 16 pg/mL [conversion factor to SI unit, 3.67]), respectively, at baseline and remained unchanged during the entire treatment period. Conclusion: These data indicate that recombinant FSH treatment increases serum FSH in a dose-proportional fashion, increases inhibin secretion, and lacks intrinsic LH activity.