Effects of exercise-induced weight loss on acylated and unacylated ghrelin in overweight children
ABSTRACT Controversial data on ghrelin concentration during exercise in human subjects have been published. We tested the hypothesis that exercise could affect acylated ghrelin (AG) and unacylated ghrelin (UAG), which could partly explain the previously reported inconsistent findings on the association of exercise with changes in ghrelin.
A prospective randomized study.
We randomized 17 overweight volunteers (11-year-old boys) to a 12-week combined exercise group (EG, n = 8) or control group (CG, n = 9). At baseline, 1, 4 and 12 weeks, we measured body weight and composition, insulin, leptin, total ghrelin and acylated ghrelin.
Compared with the CG, body weight, percentage body fat and homeostatic model assessment (HOMA) indices were significantly lower throughout the 12 weeks in the EG. Total ghrelin and UAG levels gradually increased to 131.9 +/- 5.2% and 130.4 +/- 5.2% of baseline, respectively, at week 12 in the EG, whereas AG concentration remained unchanged throughout the 12 weeks both within each group and between the groups. At week 12, there were differences in the total ghrelin level and UAG level between the groups.
This study shows an increase in unacylated acylated ghrelin and unchanged acylated ghrelin after a 12-week combined exercise programme in overweight children. These findings provide evidence of favourable effects of exercise on improving energy metabolism.
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ABSTRACT: The purpose of this study was to investigate the effects of 12 weeks of exercise training on gut hormone levels after a single bout of exercise in middle-aged Japanese women. Twenty healthy middle-aged women were recruited for this study. Several measurements were performed pre and post exercise training, including: body weight and composition, peak oxygen consumption (peak VO2), energy intake after the single bout of exercise, and the release of gut hormones with fasting and after the single bout of exercise. Exercise training resulted in significant increases in acylated ghrelin fasting levels (from 126.6 ± 5.6 to 135.9 ± 5.4 pmol/l, P < 0.01), with no significant changes in GLP-1 (from 0.54 ± 0.04 to 0.55 ± 0.03 pmol/ml) and PYY (from 1.20 ± 0.07 to 1.23 ± 0.06 pmol/ml) fasting levels. GLP-1 levels post exercise training after the single bout of exercise were significantly higher than those pre exercise training (areas under the curve (AUC); from 238.4 ± 65.2 to 286.5 ± 51.2 pmol/ml x 120 min, P < 0.001). There was a tendency for higher AUC for the time courses of PYY post exercise training than for those pre exercise training (AUC; from 519.5 ± 135.5 to 551.4 ± 128.7 pmol/ml x 120 min, P = 0.06). Changes in (delta) GLP-1 AUC were significantly correlated with decreases in body weight (r = -0.743, P < 0.001), body mass index (r = -0.732, P < 0.001), percent body fat (r = -0.731, P < 0.001), and energy intake after a single bout exercise (r = -0.649, P < 0.01) and increases in peak VO2 (r = 0.558, P < 0.05). These results suggest that the ability of exercise training to create a negative energy balance relies not only directly on its impact on energy expenditure, but also indirectly on its potential to modulate energy intake.SpringerPlus 12/2013; 2(1):83. DOI:10.1186/2193-1801-2-83
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ABSTRACT: This study investigated the effects of a long bout of aerobic exercise on hunger and energy intake and circulating levels of leptin and acylated ghrelin. Ten healthy male subjects undertook two, 4 h trials in a randomized crossover design. In the exercise trial subjects ran for 105 min at 50% of maximal oxygen uptake and the last 15 min at 70% of maximal oxygen uptake followed by a 120 min rest period. In the control trial, subjects rested for 4 h. Subjects consumed a buffet test meal at 180 min during each trial. Hunger ratings, acylated ghrelin, leptin, glucose and insulin concentrations were measured at 0, 1, 2, 3 and 4 h. No differences were found at baseline values for hunger, acylated ghrelin, leptin, insulin and glucose for both trials (p > 0.05). The estimated energy expenditure of the exercise trial was 1550 ± 136 kcal. Exercise did not change subsequent absolute energy intake, but produced a significant decrease (p < 0.05) in relative energy intake. A two-way ANOVA revealed a significant (p < 0. 05) interaction effect for hunger and acylated ghrelin. In conclusion, this exercise regimen had a positive effect on reducing appetite which is related to reduced acylated ghrelin responses over time. This finding lends support for a role of exercise in weight management. Key pointsPhysical exercise is a strategy used to counteract obesity, since it lowers the energetic balance by increasing energy expenditure. However, because any energy expended in exercise elevates the intensity of hunger and drives food consumption, it is pertinent to ask how effective exercise could be in helping people to lose weight or to prevent weight gain.The effects of exercise on hunger sensations and food intake are fairly controversial and depend on the intensity and duration of exercise.120 min prolonged treadmill exercise with mix intensity, temporarily decreased hunger sensations, acylated ghrelin and relative energy intake.Variations in exercise intensity should theoretically be a useful means of weight loss.Journal of sports science & medicine 01/2011; 10(2):283-91. · 0.90 Impact Factor
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ABSTRACT: Ghrelin and agouti-related protein (AgRP) are orexigenic peptides secreted from stomach mucosa and the arcuate nucleus of the hypothalamus, respectively. Both peptides affect feeding behavior and play a role in energy balance, glucose homeostasis, and adiposity. The purpose of the current study was to determine the effects of moderate-term (6 weeks) running regimen on resting levels of ghrelin, AgRP, adenosine triphosphate, and glycogen in soleus muscle as well as plasma concentrations of the orexigenic hormones. Eighteen adult Wistar male rats (12 weeks old, 235-255 g) were randomly assigned to training (n = 10) and control (n = 8) groups. The training group ran for 60 min/d, 5d/wk at 25 m/min and 0% grade for 6 weeks. Forty-eight hours after the last exercise session, rats were killed; and soleus muscle and plasma were collected and frozen in liquid nitrogen for later analysis. Results demonstrated that 6 weeks of treadmill exercise reduced ghrelin and increased AgRP levels in plasma. Trained rat soleus muscle had higher levels of glycogen but not adenosine triphosphate or AgRP compared with untrained controls. Data indicate that training lowers ghrelin levels in rat soleus and plasma, which is accompanied by higher plasma AgRP and soleus glycogen content.Metabolism: clinical and experimental 08/2009; 58(12):1747-52. DOI:10.1016/j.metabol.2009.06.002 · 3.61 Impact Factor