Obese adolescents exhibit a constant ratio of GH isoforms after whole body vibration and maximal voluntary contractions.
BMC Endocr Disord
; 18(1): 96, 2018 Dec 27.
Article
em En
| MEDLINE
| ID: mdl-30587244
ABSTRACT
BACKGROUND:
Growth hormone (GH) is a heterogeneous protein composed of several molecular isoforms, the most abundant ones being the 22 kDa- and 20 kDa-GH. Exercise-induced secretion of GH isoforms has been extensively investigated in normal-weight individuals due to antidoping purposes, particularly recombinant human GH (rhGH) abuse. On the other hand, the evaluation of exercise-induced responses in GH isoforms has never been performed in obese subjects.METHODS:
The acute effects of whole body vibration (WBV) or maximal voluntary contraction (MVC) alone and the combination of MVC with WBV (MVC + WBV) on circulating levels of 22 kDa- and 20 kDa-GH were evaluated in 8 obese male adolescents [mean age ± SD 17.1 ± 3.3 yrs.; weight 107.4 ± 17.8 kg; body mass index (BMI) 36.5 ± 6.6 kg/m2; BMI standard deviation score (SDS) 3.1 ± 0.6].RESULTS:
MVC (alone or combined with WBV) significantly stimulated 22 kDa- and 20 kDa-GH secretion, while WBV alone was ineffective. In particular, 22 kDa- and 20 kDa-GH peaks were significantly higher after MVC + WBV and MVC than WBV. In addition, 22 kDa-GH (but not 20 kDa-GH) peak was significantly higher after MVC + WBV than MVC. Importantly, the ratio of circulating levels of 22 kDa- to 20 kDa-GH was constant throughout the time window of evaluation after exercise and similar among the three different protocols of exercise.CONCLUSIONS:
The results of the present study confirm the ability of MVC, alone and in combination with WBV, to stimulate both 22 kDa- and 20 kDa-GH secretion in obese patients, these responses being related to the exercise workload. Since the ratio of 22 kDa- to 20 kDa-GH is constant after exercise and independent from the protocols of exercise as in normal-weight subjects, hyposomatotropism in obesity does not seem to depend on an unbalance of circulating GH isoforms. Since the present study was carried out in a small cohort of obese sedentary adolescents, these preliminary results should be confirmed in further future studies enrolling overweight/obese subjects with a wider age range.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vibração
/
Hormônio do Crescimento Humano
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Contração Muscular
/
Obesidade
Limite:
Adolescent
/
Adult
/
Humans
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Male
Idioma:
En
Revista:
BMC Endocr Disord
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Itália