Serum IGF-I levels and IGF-I gene splicing in muscle of healthy young males receiving rhGH
| Autor: | Geoffrey Goldspink, LJ Bradley, Pierre Bouloux, M Hameed, Stephen D. R. Harridge, M Aperghis, Theresa Brothwood, Cristiana P. Velloso |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Adult
Male medicine.medical_specialty Vastus lateralis muscle Endocrinology Diabetes and Metabolism medicine.medical_treatment Growth hormone Placebo law.invention Young Adult Endocrinology Randomized controlled trial law Internal medicine medicine Humans splice Insulin-Like Growth Factor I Young adult Muscle Skeletal Exercise Human Growth Hormone business.industry Growth factor Crossover study Recombinant Proteins Alternative Splicing Liver business |
| Zdroj: | Growth Hormone & IGF Research. 19:61-67 |
| ISSN: | 1096-6374 |
| DOI: | 10.1016/j.ghir.2008.07.002 |
| Popis: | Elevated growth hormone (GH) levels lead to increased circulating insulin-like growth factor-I (IGF-I), but the effects on localised muscle IGF-I splice variant expression is not known. The effects of rhGH administration, with or without an acute bout of high resistance exercise, were measured on serum IGF-I and on the mRNA levels of IGF-I splice variants in the vastus lateralis muscle of healthy young men.The study was a randomised double blind trial with a crossover design. Seven subjects were randomly assigned to a group receiving daily injections of rhGH (0.075IU kg(-1)day(-1)) or placebo for a two week period. Following a one month washout, the groups were reversed.Administration of rhGH increased circulating IGF-I from 31.8+/-3.2 to 109+/-5.4 nmol/L (p0.05). There was no effect of the exercise bout. RNA was extracted from muscle biopsies obtained from exercised and non-exercised legs 2.5h after the cessation of the exercise. Transcript expression was measured using Real-time QPCR. There was no effect of either exercise or rhGH administration on IGF-I 5' (Class 1 or Class 2) or 3' (IGF-IEa, or MGF) transcripts.Although rhGH administration has an effect on liver IGF-I expression, as shown by increase in circulating IGF-I, muscle IGF-I expression is unaffected in young healthy subjects with normal GH profile. The findings contrast with those of a previous study in which GH deficient elderly men showed higher muscle IGF-I 3' splice variant levels following rhGH administration with and without resistance training. Unlike in the liver, muscle Class1 and 2 IGF-I expression do not change significantly following administration of rhGH. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect