Regulation of appetite in lean and obese adolescents after exercise: role of acylated and desacyl ghrelin.
BACKGROUND
Increased physical activity is an integral part of weight loss programs in adolescents. We hypothesized that exercise could affect appetite-regulating hormones and the subjective desire to eat, which could partly explain the poor success rate of the existing interventions.


OBJECTIVE
The objective of this study was to investigate prospectively the effects of exercise on acylated ghrelin (AG) and desacyl ghrelin (DG) concentrations and on appetite.


METHODS
The setting for this study was a tertiary care center.


METHODS
Normal-weight [NW; body mass index (mean +/- se), 20.7 +/- 0.5 kg/m2] and overweight (OW; body mass index, 32.4 +/- 1.7) male adolescents (n = 17/group, age 15.3 +/- 0.2 yr) were studied.


METHODS
Those studied participated in 5 consecutive days of aerobic exercise (1 h/d).


RESULTS
Changes in AG and DG concentrations and in appetite during a test meal were studied.


RESULTS
Exercise did not significantly affect insulin sensitivity or body weight. Fasting total (AG and DG) ghrelin concentrations were lower in OW (600 +/- 33 pg/ml) compared with NW (764 +/- 33 pg/ml, P < 0.05) boys and were not affected by exercise. In contrast, there was a differential effect of exercise on both AG and DG (P <or= 0.019). AG significantly increased after exercise, and this increase was greater in NW compared with OW adolescents (P < 0.05). Higher AG concentrations were correlated with an increase in markers of appetite (P < 0.05).


CONCLUSIONS
Exercise differentially affects AG and DG in NW and OW male adolescents. Our data suggest that total ghrelin does not adequately reflect AG and DG concentrations and that the influence of exercise-induced hormonal changes should be considered to ensure success in weight management.
Mackelvie
Kerry J
KJ
Endocrinology and Diabetes Unit, Room K4-212, British Columbia's Children's Hospital, 4480 Oak Street, Vancouver, British Columbia, Canada V6H 3V4.
Meneilly
Graydon S
GS
Elahi
Dariush
D
Wong
Alfred C K
AC
Barr
Susan I
SI
Chanoine
Jean-Pierre
JP
D000215:Acylation; D000293:Adolescent; D001066:Appetite / Q000502:physiology*; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005215:Fasting / Q000502:physiology; D054439:Ghrelin; D006801:Humans; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D009765:Obesity / Q000378:metabolism* / Q000503:physiopathology*; D036361:Peptide Hormones / Q000097:blood*; D013739:Testosterone / Q000097:blood
D001786:Blood Glucose; D054439:Ghrelin; D007328:Insulin; D036361:Peptide Hormones; C422650:ghrelin, des-n-octanoyl; D013739:Testosterone; D007334:Insulin-Like Growth Factor I