Whey protein potentiates the intestinotrophic action of glucagon-like peptide-2 in parenterally fed rats.

Abstract

Glucagon-like peptide-2 (GLP-2) is a nutrient-regulated intestinotrophic hormone derived from proglucagon in the distal intestine. Enteral nutrients (EN) potentiate the action of GLP-2 to reverse parenteral nutrition (PN)-induced mucosal hypoplasia. The objective was to determine what enteral protein component, casein, soy, or whey protein, potentiates the intestinal growth response to GLP-2 in rats with PN-induced mucosal hypoplasia. Rats received PN and continuous intravenous infusion of GLP-2 (100 microg/kg/day) for 7 days. Six EN groups received PN+GLP-2 for days 1-3 and partial PN+GLP-2 plus EN for days 4-7. EN was provided by ad libitum intake of a semielemental liquid diet with different protein sources: casein, hydrolyzed soy, whey protein concentrate (WPC), and hydrolyzed WPC+casein. Controls received PN+GLP-2 alone. EN induced significantly greater jejunal sucrase activity and gain of body weight, and improved feed efficiency compared with PN+GLP-2 alone. EN induced greater ileal proglucagon expression, increased plasma concentration of bioactive GLP-2 by 35%, and reduced plasma dipeptidyl peptidase IV (DPP-IV) activity compared with PN+GLP-2 alone, P < 0.05. However, only whey protein, and not casein or soy, potentiated the ability of GLP-2 to reverse PN-induced mucosal hypoplasia and further increase ileal villus height, crypt depth, and mucosa cellularity compared with PN+GLP-2 alone, P < 0.05. The ability of whey protein to induce greater mucosal surface area was associated with decreased DPP-IV activity in ileum and colon compared with casein, soy, or PN+GLP-2 alone, P < 0.05. In conclusion, whey protein potentiates the action of GLP-2 to reverse PN-induced mucosal hypoplasia in association with decreased intestinal DPP-IV activity.

• Authors: Xiaowen Liu, Sangita G Murali, Jens J Holst, Denise M Ney
• Journal: American journal of physiology. Regulatory, integrative and comparative physiology (Am J Physiol Regul Integr Comp Physiol) Vol. 297 Issue 5 Pg. R1554-62 (Nov 2009) ISSN: 1522-1490 [Electronic] United States
• PMID: 19776251 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Glucagon-Like Peptide 2
• Milk Proteins
• Whey Proteins
• Proglucagon
• Sucrase
• Dipeptidyl Peptidase 4

Topics

• Animals
• Body Weight (physiology)
• Dipeptidyl Peptidase 4 (metabolism)
• Dose-Response Relationship, Drug
• Eating (physiology)
• Glucagon-Like Peptide 2 (blood, pharmacology)
• Intestinal Mucosa (drug effects, growth & development, metabolism)
• Intestines (drug effects, growth & development)
• Male
• Milk Proteins (pharmacology)
• Models, Animal
• Parenteral Nutrition
• Proglucagon (metabolism)
• Rats
• Rats, Sprague-Dawley
• Sucrase (metabolism)
• Whey Proteins