No effect of growth hormone administration on substrate oxidation during exercise in young, lean men.
J Physiol
; 567(Pt 3): 1035-45, 2005 Sep 15.
Article
em En
| MEDLINE
| ID: mdl-16002451
ABSTRACT
The purpose of this study was to examine the effects of increased fat availability induced by growth hormone (GH) administration on the oxidative metabolism during exercise. Seven well-trained males (age 25 +/- 2 years (mean +/- S.E.M.); peak oxygen consumption 62 +/- 1 ml min(-1) kg(-1) (completed four randomised trials 120 min bicycling at 55% 4 h after receiving either 7.5 IU (2.5 mg) GH or placebo (Plc), and during rest after receiving either GH or Plc. In all studies a standardized meal was given 2 h after GH or Plc injection. GH administration resulted in an approximately 60-fold increase in serum GH concentration at rest (P < 0.0001) and during exercise (P < 0.0001). The increase in serum GH was followed by an increase in circulating glycerol at rest (8%, P < 0.0001). When combined with exercise the increase in plasma glycerol was more pronounced (GH 716% of baseline versus Plc 328%, P < 0.0001). However, this increase in fat mobilization did not increase fat oxidation during exercise (indirect calorimetry). In conclusion, GH administration combined with aerobic exercise increased lipolytic parameters substantially more than exercise alone, but did not further augment whole body fat oxidation.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Exercício Físico
/
Hormônio do Crescimento Humano
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Ácidos Graxos não Esterificados
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Glicerol
Tipo de estudo:
Clinical_trials
Limite:
Adolescent
/
Adult
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Humans
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Male
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article