Local administration of growth hormone stimulates tendon collagen synthesis in elderly men

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Poul Erik Vestergaard, Jens Otto Lunde Jørgensen, Jens Olesen, Ermina Bosnjak, Lars Holm, Jan Frystyk, Henning Langberg, Michael Kjaer, Mette Damborg Hansen

Tendon collagen content and circulating growth hormone (GH) are reduced in elderly. In a placebo-controlled, double-blinded study, we examined if local injections of rhGH enhance collagen synthesis in healthy elderly men (61 ± 1 yr). Two injections of rhGH or saline (control) were injected into each of the patient's patellar tendons, respectively. Subsequently, tendon collagen fractional synthesis rate (FSR) and an indirect marker of type I collagen synthesis (PINP) were measured. Within the first 6 h after the last injections, a tendency towards a higher tendon collagen FSR was observed in 10 out of 12 subjects (P = 0.08). Similarly, PINP was higher 3-4 h after the last GH injection (P = 0.05). Serum IGF-I did not change from baseline, whereas peritendinous bioactive IGF-I was higher in the GH leg vs. control (P = 0.05). In conclusion, local injections of rhGH increase tendon collagen synthesis in humans, either directly or indirectly by increasing local bioactive IGF-I.
Original languageEnglish
JournalJournal of Applied Physiology
Issue number9
Pages (from-to)1432-8
Number of pages7
Publication statusPublished - Nov 2012

ID: 44832886