Endocrine Abstracts

Background

The gut hormone peptide YY (PYY) is released postprandially acting as a satiety signal. Obese adults have reduced concentrations of PYY in the fasting and postprandial state. Animal data suggest that lower PYY levels are likely to be a consequence rather than a cause of obesity. We aimed to investigate PYY in the fasting state and after a 420 kcal meal in post pubertal children.

Method

Nine normal weight (BMI SDS 0.96±0.27(mean±SEM)) and six obese (BMI SDS 10.2±0.74) adolescents received a test meal of 420 kcal. The adolescents were aged 14.1±0.25 and 14.6±0.29 years respectively. Venous blood was obtained at 0, 30, 60, 90 and 120 minutes. PYY was measured using an established in-house assay.

Results

PYY concentration reached a peak 60 minutes after the meal in both groups. Fasting and peak PYY concentrations were similar in normal weight (30.2 ± 2.2 increasing to 43.5 ± 5.7 pmol/L) and obese (30.2 ± 3.5 increasing to 40.8 ± 2.9 pmol/L) adolescents (p=0.99 and p=0.73). There was no difference between the area under the curve in the normal weight (4612 ± 499 pmol/L/min) and obese (4505 ± 349 pmol/L/min) groups (p=0.88). Both normal weight and obese adolescents had a significant increment in postprandial PYY concentration compared to baseline. These results are in striking contrast to those of obese adults in whom lower PYY concentrations have been reported for both fasting and postprandial levels.

Conclusion

Control of appetite during adolescence is complex and likely to evolve with developmental stage of the child. Differences between children and adults may have implications for pharmacological and dietary interventions for the increasing number of obese children presenting to clinical services. Further work is needed to examine the control of appetite in childhood.