Glucagon-like peptide-2 acutely increases proximal small intestinal blood flow in TPN-fed neonatal piglets

Glucagon- like peptide-2 (GLP-2) is a gut hormone that is secreted in response to enteral feeding and stimulates small intestinal mucosal growth. We have previously shown that GLP-2 infusion acutely increases portal venous blood flow in TPN-fed piglets. The aim of this study was to localize the vasoactive effect of GLP-2 within the gastrointestinal tissues and other visceral organs in TPN-fed piglets. Tissue blood flow rates were quantified using fluorescent microsphere deposition in anesthetized TPN-fed piglets given intravenous infusion of GLP- 2 at either 500 pmol (.) kg(-1) (.) h(-1) (low GLP-2, n = 7 pigs) or 2,000 pmol (.) kg(-1) (.) h(-1) ( high GLP-2, n = 8 pigs) for 2 h. Compared with baseline, the low and the high GLP- 2 treatment significantly increased the blood flow rate in the duodenum (+ 77%) and jejunum (+ 40% and 80%), respectively, but blood flow to the distal small intestine and colon (- 15%) was unchanged or slightly decreased. Baseline mucosal blood flow was five- fold higher than serosal blood flow; however, high GLP-2 treatment increased serosal (+ 140%) to a larger degree than mucosal blood flow (+ 73%). The high GLP-2 dose increased pancreatic flow (+ 34%) but decreased blood flow in the kidneys (- 14%) and stomach (- 12%), whereas the spleen and brain were unaffected. These findings suggest that the acute GLP-2-mediated stimulation of portal blood flow in TPN-fed piglets occurs principally via increased blood flow through the superior mesenteric artery to the proximal small intestine, a tissue region where the GLP-2R mRNA abundance and trophic GLP-2 effects are greatest.