Release of Lipids Stored in the Intestine by Glucagon-Like Peptide-2 Involves a Gut-Brain Neural Pathway.

Background: The gut hormone GLP-2 (glucagon-like peptide-2) plays important roles in lipid handling in the intestine. During postabsorptive stage, it releases preformed chylomicrons stored in the intestine, the underlying mechanisms of which are not well understood. Previous studies implicate the involvement of neural pathways in GLP-2's actions on lipid absorption in the intestine, but the role of such mechanisms in releasing postabsorptive lipid storage has not been established.

Methods: Here, in mesenteric lymph duct cannulated rats, we directly tested whether gut-brain neural communication mediates GLP-2's effects on postabsorptive lipid mobilization in the intestine. We performed total subdiaphragmatic vagotomy to disrupt the gut-brain neural communication and analyzed lipid output 5 hours after a lipid load in response to intraperitoneal GLP-2 or saline.

Results: Peripheral GLP-2 administration led to increased lymph lipid output and activation of proopiomelanocortin neurons in the arcuate nucleus of hypothalamus. Disruption of gut-brain neural communication via vagotomy blunted GLP-2's effects on promoting lipid release in the intestine.

Conclusions: These results, for the first time, demonstrate a novel mechanism in which postabsorptive mobilization of intestinal lipid storage by GLP-2 enlists a gut-brain neural pathway.