Wang, P. Y. et al. Upper intestinal lipids trigger a gut-brain-liver axis to regulate glucose production. Nature 452, 1012-1016

Toronto General Hospital Research Institute, University Health Network, Toronto M5G 1L7, Canada.
Nature (Impact Factor: 41.46). 05/2008; 452(7190):1012-6. DOI: 10.1038/nature06852
Source: PubMed


Energy and glucose homeostasis are regulated by food intake and liver glucose production, respectively. The upper intestine has a critical role in nutrient digestion and absorption. However, studies indicate that upper intestinal lipids inhibit food intake as well in rodents and humans by the activation of an intestine-brain axis. In parallel, a brain-liver axis has recently been proposed to detect blood lipids to inhibit glucose production in rodents. Thus, we tested the hypothesis that upper intestinal lipids activate an intestine-brain-liver neural axis to regulate glucose homeostasis. Here we demonstrate that direct administration of lipids into the upper intestine increased upper intestinal long-chain fatty acyl-coenzyme A (LCFA-CoA) levels and suppressed glucose production. Co-infusion of the acyl-CoA synthase inhibitor triacsin C or the anaesthetic tetracaine with duodenal lipids abolished the inhibition of glucose production, indicating that upper intestinal LCFA-CoAs regulate glucose production in the preabsorptive state. Subdiaphragmatic vagotomy or gut vagal deafferentation interrupts the neural connection between the gut and the brain, and blocks the ability of upper intestinal lipids to inhibit glucose production. Direct administration of the N-methyl-d-aspartate ion channel blocker MK-801 into the fourth ventricle or the nucleus of the solitary tract where gut sensory fibres terminate abolished the upper-intestinal-lipid-induced inhibition of glucose production. Finally, hepatic vagotomy negated the inhibitory effects of upper intestinal lipids on glucose production. These findings indicate that upper intestinal lipids activate an intestine-brain-liver neural axis to inhibit glucose production, and thereby reveal a previously unappreciated pathway that regulates glucose homeostasis.

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    • "Accumulating evidence arising from physiological (Chi and Powley, 2007; Tellez et al., 2013; Wang et al., 2008), electrophysiological (Lal et al., 2001; Randich et al., 2000), and biochemical (de Lartigue et al., 2011; Duca et al., 2013; Paulino et al., 2009) studies have established that vagal sensory neurons respond to both acute and long-term changes in nutritional status including that of dietary-derived lipids. The acute response of vagal afferents to intestinal lipids are thought to be regulated by gut peptides and neurotransmitters that are transiently released from the neighboring enteroendocrine cells (Glatzle et al., 2003; Raybould et al., 1998; Moran et al., 1997). "
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