Objectives Lipid mediators in the GI tract regulate satiation and satiety. Bile acids (BAs) regulate the absorption and metabolism of dietary lipid in the intestine, but their effects on lipid-regulated satiation and satiety are completely unknown. Investigating this is challenging because introducing excessive BAs or eliminating BAs strongly impacts GI functions. We used a mouse model (Cyp8b1–/– mice) with normal total BA levels, but alterations in the composition of the BA pool that impact multiple aspects of intestinal lipid metabolism. We tested two hypotheses: BAs affect food intake by (1) regulating production of the bioactive lipid oleoylethanolamide (OEA), which enhances satiety; or (2) regulating the quantity and localisation of hydrolysed fat in small intestine, which controls gastric emptying and satiation.
Design We evaluated OEA levels, gastric emptying and food intake in wild-type and Cyp8b1–/– mice. We assessed the role of the fat receptor GPR119 in these effects using Gpr119–/– mice.
Results Cyp8b1–/– mice on a chow diet showed mild hypophagia. Jejunal OEA production was blunted in Cyp8b1–/– mice, thus these data do not support a role for this pathway in the hypophagia of Cyp8b1–/– mice. On the other hand, Cyp8b1 deficiency decreased gastric emptying, and this was dependent on dietary fat. GPR119 deficiency normalised the gastric emptying, gut hormone levels, food intake and body weight of Cyp8b1–/– mice.
Conclusion BAs regulate gastric emptying and satiation by determining fat-dependent GPR119 activity in distal intestine.
- bile acid
- gastric emptying
- small intestine
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
Statistics from Altmetric.com
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Correction notice This article has been corrected since it published Online First. The author names have been amended and figure 5 updated.
Contributors SH and RH conceived and designed research; SH, TRA, DAA, PAP and CZ performed experiments; GJS taught the method for implanting duodenal catheters and provided valuable feedback; SH, ND and RH analysed data; SH and RH drafted manuscript; all authors edited the manuscript.
Funding This work was supported by the Russell Berrie Foundation, NIH/NIDDK (R01DK115825), and the American Diabetes Association (1-18-IBS-275) to RH, Kanae foreign study grant to SH, and NIH grants T32DK007328 to TRA, DK119498, DA034009 and DK114978 to ND.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval All experiments were approved and conducted according to the guidance of the Columbia University Institutional Animal Care and Use Committee.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.