Publication

Gut protein uptake and mechanisms of meal-induced cortisol release

Journal Paper/Review - Mar 1, 2005

Units
PubMed
Doi

Citation
Benedict C, Hallschmid M, Scheibner J, Niemeyer D, Schultes B, Merl V, Fehm H, Born J, Kern W. Gut protein uptake and mechanisms of meal-induced cortisol release. The Journal of clinical endocrinology and metabolism 2005; 90:1692-6.
Type
Journal Paper/Review (English)
Journal
The Journal of clinical endocrinology and metabolism 2005; 90
Publication Date
Mar 1, 2005
Issn Print
0021-972X
Pages
1692-6
Brief description/objective

The enhanced cortisol release after protein-rich meals might represent a neuroendocrine response to food allergens. We tested whether the antigenicity of proteins contributes to this effect. Twelve healthy men nasogastrically received casein, its less allergenic hydrolysate, and placebo. Contrary to expectations, secretion of cortisol (area under the curve, 742.70 +/- 73.48 vs. 542.95 +/- 70.31 micromol/liter.min, P < 0.03) and ACTH (2020.21 +/- 251.10 vs. 1649.82 +/- 241.23 micromol/liter.min, P < 0.05) was stronger on casein-hydrolysate than casein. Systemic immune activity remained unaffected as indicated by unchanged IL-6 plasma concentrations. This finding indicates that the grade of hydrolysis of a protein and the presence of particular amino acids, rather than its antigenicity, are crucial for the pituitary-adrenal response to nutrients. To further examine whether this response is triggered at the gastrointestinal mucosa or after the substance has reached the circulation, in a supplementary experiment, amino acids were given either nasogastrically or iv to healthy men (n = 4). Only the nasogastric infusion of amino acids induced a significant rise in cortisol concentrations. Serum concentrations of tryptophan, which is known to directly excite the hypothalamo-pituitary-adrenal axis, were comparable for both conditions. We conclude that the meal-related hypothalamo-pituitary-adrenal axis response to amino acids results from a signal that rather acts at the gastrointestinal mucosa than directly via the circulating blood.