Presented in part at the Annual Meeting of the American Society for Bone and Mineral Research Meeting, San Francisco, CA, U.S.A., 1996.
Oral Administration of the Growth Hormone Secretagogue MK-677 Increases Markers of Bone Turnover in Healthy and Functionally Impaired Elderly Adults†
Article first published online: 1 JUL 1999
Copyright © 1999 ASBMR
Journal of Bone and Mineral Research
Volume 14, Issue 7, pages 1182–1188, July 1999
How to Cite
Murphy, M. G., Bach, M. A., Plotkin, D., Bolognese, J., Ng, J., Krupa, D., Cerchio, K. and Gertz, B. J. (1999), Oral Administration of the Growth Hormone Secretagogue MK-677 Increases Markers of Bone Turnover in Healthy and Functionally Impaired Elderly Adults. J Bone Miner Res, 14: 1182–1188. doi: 10.1359/jbmr.1918.104.22.1682
- Issue published online: 2 DEC 2009
- Article first published online: 1 JUL 1999
- Manuscript Accepted: 25 FEB 1999
- Manuscript Revised: 28 JAN 1999
- Manuscript Received: 20 AUG 1998
Growth hormone (GH) stimulates osteoblasts in vitro and increases bone turnover and stimulates osteoblast activity when given to elderly subjects. Probably a major effect of GH on bone is mediated through stimulation of either circulating or locally produced insulin-like growth factor I (IGF-I). We determined the effect of chronic administration of the GH secretagogue, MK-677, on serum IGF-I and markers of bone turnover in 187 elderly adults (65 years or older) enrolled in three randomized, double-blind, placebo-controlled clinical studies lasting 2–9 weeks. Urine was collected for determination of N-telopeptide cross-links (NTXs), a marker of bone resorption, and blood was collected for determination of serum osteocalcin and bone-specific alkaline phosphatase (BSAP), as bone formation markers, and serum IGF-I levels pre- and post-treatment. Dose response data were initially obtained in healthy elderly subjects who received oral doses of 10 mg or 25 mg of MK-677 or placebo for 2 weeks (n = 10–12/group). Treatment with 10 mg and 25 mg of MK-677 for 2 weeks increased mean urine NTXs 10% and 17%, respectively (p < 0.05 vs. placebo). Additionally, 50 healthy elderly subjects received either placebo (n = 20) for 4 weeks or 25 mg of MK-677 (n = 30) daily for 2 weeks followed by 50 mg daily for 2 weeks. MK-677 increased mean serum osteocalcin by 8% (p < 0.05 vs. placebo). In both studies, MK-677 increased serum IGF-I levels significantly (55–94%). Subsequently, the biological effects of MK-677 were studied in 105 elderly subjects who met objective criteria for functional impairment. Subjects were randomized to receive oral doses of placebo for 9 weeks or either 5, 10, or 25 mg of MK-677 daily for an initial 2 weeks followed by 25 mg of MK-677 daily for the next 7 weeks(n = 63 on MK-677 and n = 28 on placebo completed 9 weeks of therapy). Treatment with MK-677 (all MK-677 groups combined) for 9 weeks increased mean serum osteocalcin by 29.4% and BSAP by 10.4% (p < 0.001 vs. placebo) and mean urinary NTX excretion by 22.6% (p < 0.05 vs. placebo). The change from baseline serum osteocalcin correlated with the change from baseline serum IGF-I in the MK-677 group (r = 0.37; p < 0.01). In conclusion, once daily dosing with MK-677, an orally active GH secretagogue, stimulates bone turnover in elderly subjects based on elevations in biochemical markers of bone resorption and formation.