GLP-1 reduces intestinal lymph flow, triglyceride absorption, and apolipoprotein production in rats.
Glucagon-like peptide 1 (GLP-1) is a gastrointestinal hormone secreted in response to meal ingestion by enteroendocrine L cells located predominantly in the lower small intestine and large intestine. GLP-1 inhibits the secretion and motility of the upper gut and has been suggested to play a role in the "ileal brake." In this study, we investigated the effect of recombinant GLP-1-(7-36) amide (rGLP-1) on lipid absorption in the small intestine in intestinal lymph duct-cannulated rats. In addition, the effects of rGLP-1 on intestinal production of apolipoprotein (apo) B and apo A-IV, two apolipoproteins closely related to lipid absorption, were evaluated. rGLP-1 was infused through the jugular vein, and lipids were infused simultaneously through a duodenal cannula. Our results showed that infusion of rGLP-1 at 20 pmol.kg(-1).min(-1) caused a dramatic and prompt decrease in lymph flow from 2.22 +/- 0.15 (SE) ml/h at baseline (n = 6) to 1.24 +/- 0.06 ml/h at 2 h (P < 0.001). In contrast, a significant increase in lymph flow was observed in the saline (control) group: 2.19 +/- 0.20 and 3.48 +/- 0.09 ml/h at baseline and at 6 h of lipid infusion, respectively (P < 0.001). rGLP-1 also inhibited intestinal triolein absorption (P < 0.05) and lymphatic apo B and apo A-IV output (P < 0.05) but did not affect cholesterol absorption. In conclusion, rGLP-1 dramatically decreases intestinal lymph flow and reduces triglyceride absorption and apo B and apo A-IV production. These findings suggest a novel role for GLP-1 in lipid absorption.
Qin
Xiaofa
X
Department of Pathology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45237, USA.
Shen
Hui
H
Liu
Min
M
Yang
Qing
Q
Zheng
Shuqin
S
Sabo
Mary
M
D'Alessio
David A
DA
Tso
Patrick
P
D000818:Animals; D001054:Apolipoproteins A / Q000096:biosynthesis*; D001055:Apolipoproteins B / Q000096:biosynthesis*; D005934:Glucagon; D052216:Glucagon-Like Peptide 1; D004763:Glucagon-Like Peptides; D007408:Intestinal Absorption / Q000502:physiology; D007413:Intestinal Mucosa / Q000502:physiology; D007421:Intestine, Small / Q000378:metabolism / Q000502:physiology*; D008196:Lymph / Q000502:physiology*; D008297:Male; D010446:Peptide Fragments / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins; D013997:Time Factors; D014280:Triglycerides / Q000378:metabolism*
D001054:Apolipoproteins A; D001055:Apolipoproteins B; D010446:Peptide Fragments; D011994:Recombinant Proteins; D014280:Triglycerides; C022205:apolipoprotein A-IV; C055453:glucagon-like peptide 1 (7-36)amide; D004763:Glucagon-Like Peptides; D052216:Glucagon-Like Peptide 1; D005934:Glucagon