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Ann Nutr Metab. 2003;47(6):312-8.

Endocrine effects of food intake: insulin, ghrelin, and leptin responses to a single bolus of essential amino acids in humans.

Author information

1
Department of Paediatrics, University of Erlangen-Nuremberg, Loschgestrasse 15, DE-91054 Erlangen, Germany. ina.knerr@kinder.imed.uni-erlangen.de

Abstract

BACKGROUND:

This study deals with the physiological effects of an oral bolus of essential amino acids (AA) on the secretion of insulin, ghrelin and leptin in fasting humans.

METHODS:

12 healthy adults (age 18-40 years, 10 males, 2 females, body mass index 18.0-23.5 kg/m(2)) were included in our study. Seven fasted volunteers consumed an AA mixture (0.35 g/kg BW), 5 served as controls. Serum AA, glucose, albumin, urea and hormones were measured at 0, 15, 30 min and thereafter at 30-min intervals up to 5 h.

RESULTS:

Glucose, albumin and urea remained constant, peak AA concentrations were achieved at 30 min for methionine (Met), at 60 min for all other AA. The insulin peak (533% compared to basal level, p < 0.01) at 30 min was earlier than the peaks of all AA except for Met. Ghrelin showed a continuous rise towards the end of the experiment leading to a 3-fold increase in initial concentrations in the study group (p < 0.001), significantly higher than in the control group (p < 0.05). In contrast, both groups exhibited almost constant leptin concentrations.

CONCLUSION:

Our data indicate that an oral low-dose AA bolus not only causes considerable hyperaminoacidemia and hyperinsulinemia but is also accompanied by an increased ghrelin secretion in fasted humans. This may be a specific effect or may be due to the fact that a single bolus of AA is not a sufficient stimulus to induce satiety. Leptin, however, is not a key mediator in this setting.

PMID:
14520028
DOI:
10.1159/000072405
[Indexed for MEDLINE]

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