Katharina Schilbach, Christina Gar, Andreas Lechner, Shiva Sophia Nicolay, Laura Schwerdt, Michael Haenelt, Jakob Dal, Jens-Otto Lunde Jørgensen, Sylvère Störmann, Jochen Schopohl, and Martin Bidlingmaier
Growth hormone (GH) nadir (GHnadir) during oral glucose tolerance test (OGTT) is an important tool in diagnosing acromegaly, but data evaluating the need to adjust cut-offs to biological variables utilizing today's assay methods are scarce. We therefore investigated large cohorts of healthy subjects of both sexes to define normal GHnadir concentrations for a modern, sensitive, 22 kD-GH-specific assay.
Multicenter study with prospective and retrospective cohorts (525 healthy adults: 405 females and 120 males).
GH concentrations were measured by the IDS-iSYS immunoassay after oral application of 75 g glucose.
GHnadir concentrations (µg/L) were significantly higher in lean and normal weight subjects (group A) compared to overweight and obese subjects (group B); (males (M): A vs B, mean: 0.124 vs 0.065, P = 0.0317; premenopausal females without estradiol-containing OC (OC-EE) (FPRE): A vs B, mean: 0.179 vs 0.092, P < 0.0001; postmenopausal women (FPOST): A vs B, mean: 0.173 vs 0.078, P < 0.0061). Age, glucose metabolism and menstrual cycle had no impact on GHnadir. However, premenopausal females on OC-EE (FPREOC) exhibited significantly higher GHnadir compared to all other groups (all P < 0.0001). BMI had no impact on GHnadir in FPREOC (A vs B, mean: 0.624 vs 0.274, P = 0.1228).
BMI, sex and OC-EE intake are the major determinants for the GHnadir during OGTT in healthy adults. Using a modern sensitive GH assay, GHnadir concentrations in healthy subjects are distinctly lower than cut-offs used in previous guidelines for diagnosis and monitoring of acromegaly.
Frederick Vogel, Leah Braun, German Rubinstein, Stephanie Zopp, Sarina Benedix, Holger Schneider, Katrin Ritzel, Katharina Schilbach, Ralf Schmidmaier, Felix Beuschlein, Martin Bidlingmaier, and Martin Reincke
Glucocorticoid excess leads to muscle atrophy and weakness in patients with endogenous Cushing’s syndrome. Insulin-like growth factor I (IGF-I) is known to have protective effects on muscle loss. We hypothesized that individual serum IGF-I concentrations might be predictive for long-term myopathy outcome in Cushing’s syndrome.
Patients and methods
In a prospective longitudinal study of 31 patients with florid Cushing’s syndrome, we analyzed IGF-I and IGF binding protein 3 (IGFBP 3) concentrations at the time of diagnosis and following surgical remission over a period of up to 3 years. We assessed muscle strength by grip strength measurements using a hand grip dynamometer and muscle mass by bio-impedance measurements.
Individual serum IGF-I concentrations in the postoperative phase were strongly predictive of long-term grip strength outcome (rs = 0.696, P ≤ 0.001). Also, lower IGF-I concentrations were associated with a lower muscle mass after 3 years (rs = 0.404, P = 0.033). While patients with high IGF-I s.d. scores (SDS; >1.4) showed an improvement in grip strength within the follow-up period (P = 0.009), patients with lower IGF-I SDS (≤−0.4) had a worse outcome with persisting muscle dysfunction. In contrast, preoperative IGF-I concentrations during the florid phase of Cushing’s syndrome did not predict long-term muscle function outcome (rs = 0.285, P = 0.127).
Lower individual IGF-I concentrations 6 months after curative surgery for Cushing’s syndrome are associated with adverse long-term myopathy outcome and IGF-I might be essential for muscle regeneration in the early phase after correction of hypercortisolism.
Cheol Ryong Ku, Thierry Brue, Katharina Schilbach, Stanislav Ignatenko, Sandor Magony, Yoon-Sok Chung, Byung-Joon Kim, Kyu Yeon Hur, Ho-Cheol Kang, Jung Hee Kim, Min Seon Kim, Aldona Kowalska, Marek Bolanowski, Marek Ruchala, Svetozar Damjanovic, Juraj Payer, Yun Jung Choi, Su Jin Heo, Tae Kyoung Kim, MinKyu Heo, Joan Lee, and Eun Jig Lee
Hybrid Fc-fused rhGH (GX-H9) is a long-acting recombinant human growth hormone (GH) under clinical development for both adults and children with GH deficiency (GHD). We compared the safety, pharmacokinetics and pharmacodynamics of weekly and every other week (EOW) dosages of GX-H9 with those of daily GH administration in adult GHD (AGHD) patients.
This was a randomized, open-label, active-controlled and dose-escalation study conducted in 16 endocrinology centers in Europe and Korea.
Forty-five AGHD patients with or without prior GH treatment were enrolled. Patients with prior GH treatments were required to have received the last GH administration at least 1 month prior to randomization. Subjects were sequentially assigned to treatment groups. Fifteen subjects were enrolled to each treatment group and randomly assigned to receive either GX-H9 or Genotropin (4:1 ratio). GX-H9 dosage regimens for Groups 1, 2 and 3 were 0.1 mg/kg weekly, 0.3 mg/kg EOW and 0.2 mg/kg EOW, respectively. All Genotropin-assigned subjects received 6 µg/kg Genotropin, regardless of treatment group. Main outcome analyses included measurements of serum insulin-like growth factor 1 (IGF-I), safety, pharmacokinetics, pharmacodynamics and immunogenicity.
Mean GX-H9 peak and total exposure increased with an increase in dose after a single-dose administration. The mean IGF-I response was sustained above baseline over the intended dose interval of 168 h for the weekly and 336 h for the EOW GX-H9 groups. Safety profiles and immunogenicity were not different across the treatment groups and with Genotropin.
GX-H9 has the potential for up to twice-monthly administration.