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Small intestinal CaSR-dependent and CaSR-independent protein sensing regulates feeding and glucose tolerance in rats

Nature Metabolism volume 6, pages 39–49 (2024)Cite this article

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Abstract

Proteins activate small intestinal calcium sensing receptor (CaSR) and/or peptide transporter 1 (PepT1) to increase hormone secretion1,2,3,4,5,6,7,8, but the effect of small intestinal protein sensing and the mechanistic potential of CaSR and/or PepT1 in feeding and glucose regulation remain inconclusive. Here we show that, in male rats, CaSR in the upper small intestine is required for casein infusion to increase glucose tolerance and GLP1 and GIP secretion, which was also dependent on PepT1 (ref. 9). PepT1, but not CaSR, is required for casein infusion to lower feeding. Upper small intestine casein sensing fails to regulate feeding, but not glucose tolerance, in high-fat-fed rats with decreased PepT1 but increased CaSR expression. In the ileum, a CaSR-dependent but PepT1-independent pathway is required for casein infusion to lower feeding and increase glucose tolerance in chow-fed rats, in parallel with increased PYY and GLP1 release, respectively. High fat decreases ileal CaSR expression and disrupts casein sensing on feeding but not on glucose control, suggesting an ileal CaSR-independent, glucose-regulatory pathway. In summary, we discover small intestinal CaSR- and PepT1-dependent and -independent protein sensing mechanisms that regulate gut hormone release, feeding and glucose tolerance. Our findings highlight the potential of targeting small intestinal CaSR and/or PepT1 to regulate feeding and glucose tolerance.

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Fig. 1: USI casein infusion increases glucose tolerance via a CaSR- and PepT1-dependent pathway but lowers food intake via PepT1 independently of CaSR.
Fig. 2: USI casein infusion fails to lower food intake in HF rats but still increases glucose tolerance via CaSR in association with changes in PepT1 and CaSR expression and GLP1, GIP and PYY secretion.
Fig. 3: Ileal casein hydrolysate infusion lowers food intake and increases PYY levels in chow, but not in HF, rats via CaSR.
Fig. 4: CaSR is required for ileal casein hydrolysate infusion to increase glucose tolerance in chow, but not HF, rats.

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Data reported in this study are available Source Data. Source data are provided with this paper.

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No custom code was used.

References

  1. Modvig, I. M., Kuhre, R. E. & Holst, J. J. Peptone-mediated glucagon-like peptide-1 secretion depends on intestinal absorption and activation of basolaterally located calcium-sensing receptors. Physiol. Rep. 7, e14056 (2019).

    Article  PubMed  PubMed Central  Google Scholar 

  2. Mace, O. J., Schindler, M. & Patel, S. The regulation of K- and L-cell activity by GLUT2 and the calcium-sensing receptor CasR in rat small intestine. J. Physiol. 590, 2917–2936 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  3. Acar, I., Cetinkaya, A., Lay, I. & Ileri-Gurel, E. The role of calcium sensing receptors in GLP-1 and PYY secretion after acute intraduodenal administration of L-tryptophan in rats. Nutr. Neurosci. 23, 481–489 (2020).

    Article  CAS  PubMed  Google Scholar 

  4. Diakogiannaki, E. et al. Oligopeptides stimulate glucagon-like peptide-1 secretion in mice through proton-coupled uptake and the calcium-sensing receptor. Diabetologia 56, 2688–2696 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. Modvig, I. M. et al. Amino acids differ in their capacity to stimulate GLP-1 release from the perfused rat small intestine and stimulate secretion by different sensing mechanisms. Am. J. Physiol. Endocrinol. Metab. 320, E874–E885 (2021).

    Article  CAS  PubMed  Google Scholar 

  6. Liou, A. P. et al. The extracellular calcium-sensing receptor is required for cholecystokinin secretion in response to L-phenylalanine in acutely isolated intestinal I cells. Am. J. Physiol. Gastrointest. Liver Physiol. 300, G538–G546 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  7. Nakajima, S., Hira, T. & Hara, H. Calcium-sensing receptor mediates dietary peptide-induced CCK secretion in enteroendocrine STC-1 cells. Mol. Nutr. Food Res. 56, 753–760 (2012).

    Article  CAS  PubMed  Google Scholar 

  8. Alamshah, A. et al. l-phenylalanine modulates gut hormone release and glucose tolerance, and suppresses food intake through the calcium-sensing receptor in rodents. Int J. Obes. 41, 1693–1701 (2017).

    Article  CAS  Google Scholar 

  9. Dranse, H. J. et al. Physiological and therapeutic regulation of glucose homeostasis by upper small intestinal PepT1-mediated protein sensing. Nat. Commun. 9, 1118 (2018).

    Article  PubMed  PubMed Central  Google Scholar 

  10. Bensaïd, A. et al. Protein is more potent than carbohydrate for reducing appetite in rats. Physiol. Behav. 75, 577–582 (2002).

    Article  PubMed  Google Scholar 

  11. Batterham, R. L. et al. Critical role for peptide YY in protein-mediated satiation and body-weight regulation. Cell Metab. 4, 223–233 (2006).

    Article  CAS  PubMed  Google Scholar 

  12. Geraedts, M. C. P. et al. Intraduodenal administration of intact pea protein effectively reduces food intake in both lean and obese male subjects. PLoS ONE 6, e24878 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  13. Ryan, A. T. et al. Intraduodenal protein modulates antropyloroduodenal motility, hormone release, glycemia, appetite, and energy intake in lean men. Am. J. Clin. Nutr. 96, 474–482 (2012).

    Article  CAS  PubMed  Google Scholar 

  14. Ryan, A. T. et al. Effects of intraduodenal lipid and protein on gut motility and hormone release, glycemia, appetite, and energy intake in lean men. Am. J. Clin. Nutr. 98, 300–311 (2013).

    Article  CAS  PubMed  Google Scholar 

  15. Steinert, R. E. et al. Effects of intraduodenal infusion of the branched-chain amino acid leucine on ad libitum eating, gut motor and hormone functions, and glycemia in healthy men. Am. J. Clin. Nutr. 102, 820–827 (2015).

    Article  CAS  PubMed  Google Scholar 

  16. van Avesaat, M., Ripken, D., Hendriks, H. F. J., Masclee, A. A. M. & Troost, F. J. Small intestinal protein infusion in humans: evidence for a location-specific gradient in intestinal feedback on food intake and GI peptide release. Int J. Obes. 41, 217–224 (2017).

    Article  Google Scholar 

  17. Dumoulin, V., Moro, F., Barcelo, A., Dakka, T. & Cuber, J. C. Peptide YY, glucagon-like peptide-1, and neurotensin responses to luminal factors in the isolated vascularly perfused rat ileum. Endocrinology 139, 3780–3786 (1998).

    Article  CAS  PubMed  Google Scholar 

  18. Svendsen, B. et al. An analysis of cosecretion and coexpression of gut hormones from male rat proximal and distal small intestine. Endocrinology 156, 847–857 (2015).

    Article  CAS  PubMed  Google Scholar 

  19. Hutchison, A. T. et al. Comparative effects of intraduodenal whey protein hydrolysate on antropyloroduodenal motility, gut hormones, glycemia, appetite, and energy intake in lean and obese men. Am. J. Clin. Nutr. 102, 1323–1331 (2015).

    Article  CAS  PubMed  Google Scholar 

  20. Duca, F. A., Waise, T. M. Z., Peppler, W. T. & Lam, T. K. T. The metabolic impact of small intestinal nutrient sensing. Nat. Commun. 12, 903 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  21. Drucker, D. J. Mechanisms of action and therapeutic application of glucagon-like peptide-1. Cell Metab. 27, 740–756 (2018).

    Article  CAS  PubMed  Google Scholar 

  22. Drucker, D. J. GLP-1 physiology informs the pharmacotherapy of obesity. Mol. Metab. 57, 101351 (2022).

    Article  CAS  PubMed  Google Scholar 

  23. Nogueiras, R., Nauck, M. A. & Tschöp, M. H. Gut hormone co-agonists for the treatment of obesity: from bench to bedside. Nat. Metab. 5, 933–944 (2023).

    Article  CAS  PubMed  Google Scholar 

  24. Behary, P. et al. Combined GLP-1, oxyntomodulin, and peptide YY improves body weight and glycemia in obesity and prediabetes/type 2 diabetes: a randomized, single-blinded, placebo-controlled study. Diabetes Care 42, 1446–1453 (2019).

    Article  CAS  PubMed  Google Scholar 

  25. Chichura, K. S. et al. A peptide triple agonist of GLP-1, neuropeptide Y1, and neuropeptide Y2 receptors promotes glycemic control and weight loss. Sci. Rep. 13, 9554 (2023).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  26. Maljaars, P. W. J., Peters, H. P. F., Mela, D. J. & Masclee, A. A. M. Ileal brake: a sensible food target for appetite control. A review. Physiol. Behav. 95, 271–281 (2008).

    Article  CAS  PubMed  Google Scholar 

  27. van Avesaat, M., Troost, F. J., Ripken, D., Hendriks, H. F. & Masclee, A. A. M. Ileal brake activation: macronutrient-specific effects on eating behavior? Int J. Obes. 39, 235–243 (2015).

    Article  Google Scholar 

  28. Goldstein, N. et al. Hypothalamic detection of macronutrients via multiple gut-brain pathways. Cell Metab. 33, 676–687 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  29. Symonds, E. L. et al. Mechanisms of activation of mouse and human enteroendocrine cells by nutrients. Gut 64, 618–626 (2015).

    Article  CAS  PubMed  Google Scholar 

  30. Fagerberg, L. et al. Analysis of the human tissue-specific expression by genome-wide integration of transcriptomics and antibody-based proteomics. Mol. Cell. Proteomics 13, 397–406 (2014).

    Article  CAS  PubMed  Google Scholar 

  31. van der Wielen, N. et al. Cross-species comparison of genes related to nutrient sensing mechanisms expressed along the intestine. PLoS ONE 9, e107531 (2014).

    Article  PubMed  PubMed Central  Google Scholar 

  32. Waise, T. M. Z., Lim, Y.-M., Danaei, Z., Zhang, S.-Y. & Lam, T. K. T. Small intestinal taurochenodeoxycholic acid-FXR axis alters local nutrient-sensing glucoregulatory pathways in rats. Mol. Metab. 44, 101132 (2021).

    Article  CAS  PubMed  Google Scholar 

  33. Bauer, P. V. et al. Lactobacillus gasseri in the upper small intestine impacts an ACSL3-dependent fatty acid-sensing pathway regulating whole-body glucose homeostasis. Cell Metab. 27, 572–587 (2018).

    Article  CAS  PubMed  Google Scholar 

  34. Darcel, N. P., Liou, A. P., Tomé, D. & Raybould, H. E. Activation of vagal afferents in the rat duodenum by protein digests requires PepT1. J. Nutr. 135, 1491–1495 (2005).

    Article  CAS  PubMed  Google Scholar 

  35. Wang, J. et al. Overfeeding rapidly induces leptin and insulin resistance. Diabetes 50, 2786–2791 (2001).

    Article  CAS  PubMed  Google Scholar 

  36. Côté, C. D. et al. Resveratrol activates duodenal Sirt1 to reverse insulin resistance in rats through a neuronal network. Nat. Med. 21, 498–505 (2015).

    Article  PubMed  Google Scholar 

  37. Schirra, J. et al. Gastric emptying and release of incretin hormones after glucose ingestion in humans. J. Clin. Invest. 97, 92–103 (1996).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  38. Helou, N., Obeid, O., Azar, S. T. & Hwalla, N. Variation of postprandial PYY 3-36 response following ingestion of differing macronutrient meals in obese females. Ann. Nutr. Metab. 52, 188–195 (2008).

    Article  CAS  PubMed  Google Scholar 

  39. Zadeh-Tahmasebi, M. et al. Activation of short and long chain fatty acid sensing machinery in the ileum lowers glucose production in vivo. J. Biol. Chem. 291, 8816–8824 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  40. Hayes, M. R. et al. The common hepatic branch of the vagus is not required to mediate the glycemic and food intake suppressive effects of glucagon-like-peptide-1. Am. J. Physiol. Regul. Integr. Comp. Physiol. 301, R1479–R1485 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  41. Borgmann, D. et al. Gut-brain communication by distinct sensory neurons differently controls feeding and glucose metabolism. Cell Metab. 33, 1466–1482 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  42. Iwasaki, Y. et al. GLP-1 release and vagal afferent activation mediate the beneficial metabolic and chronotherapeutic effects of D-allulose. Nat. Commun. 9, 113 (2018).

    Article  PubMed  PubMed Central  Google Scholar 

  43. Varin, E. M. et al. Distinct neural sites of GLP-1R expression mediate physiological versus pharmacological control of incretin action. Cell Rep. 27, 3371–3384 (2019).

    Article  CAS  PubMed  Google Scholar 

  44. Krieger, J.-P. et al. Knockdown of GLP-1 receptors in vagal afferents affects normal food intake and glycemia. Diabetes 65, 34–43 (2016).

    Article  CAS  PubMed  Google Scholar 

  45. Woodward, O. R. M., Gribble, F. M., Reimann, F. & Lewis, J. E. Gut peptide regulation of food intake - evidence for the modulation of hedonic feeding. J. Physiol. 600, 1053–1078 (2022).

    Article  CAS  PubMed  Google Scholar 

  46. Spanier, B. Transcriptional and functional regulation of the intestinal peptide transporter PEPT1. J. Physiol 592, 871–879 (2014).

    Article  CAS  PubMed  Google Scholar 

  47. Xu, J. et al. Calcium-sensing receptor regulates intestinal dipeptide absorption via Ca2+ signaling and IKCa activation. Physiol. Rep. 8, e14337 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  48. Richards, P. et al. High fat diet impairs the function of glucagon-like peptide-1 producing L-cells. Peptides 77, 21–27 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  49. Nunez-Salces, M., Li, H., Christie, S. & Page, A. J. The effect of high-fat diet-induced obesity on the expression of nutrient chemosensors in the mouse stomach and the gastric ghrelin cell. Nutrients 12, 2493 (2020).

  50. Liang, L.-M. et al. Diabetes downregulates peptide transporter 1 in the rat jejunum: possible involvement of cholate-induced FXR activation. Acta Pharmacol. Sin. 41, 1465–1475 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  51. Zhang, S.-Y. et al. FXR in the dorsal vagal complex is sufficient and necessary for upper small intestinal microbiome-mediated changes of TCDCA to alter insulin action in rats. Gut 70, 1675–1683 (2021).

    Article  CAS  PubMed  Google Scholar 

  52. Canaff, L. & Hendy, G. N. Calcium-sensing receptor gene transcription is up-regulated by the proinflammatory cytokine, interleukin-1β. Elem. J. Biol. Chem. 280, 14177–14188 (2005).

    Article  CAS  Google Scholar 

  53. Canaff, L., Zhou, X. & Hendy, G. N. The proinflammatory cytokine, interleukin-6, up-regulates calcium-sensing receptor gene transcription via Stat1/3 and Sp1/3. J. Biol. Chem. 283, 13586–13600 (2008).

    Article  CAS  PubMed  Google Scholar 

  54. Cifuentes, M. et al. Obesity-associated proinflammatory cytokines increase calcium sensing receptor (CaSR) protein expression in primary human adipocytes and LS14 human adipose cell line. Arch. Biochem. Biophys. 500, 151–156 (2010).

    Article  CAS  PubMed  Google Scholar 

  55. Winer, D. A., Luck, H., Tsai, S. & Winer, S. The intestinal immune system in obesity and insulin resistance. Cell Metab. 23, 413–426 (2016).

    Article  CAS  PubMed  Google Scholar 

  56. Kawano, Y. et al. Colonic pro-inflammatory macrophages cause insulin resistance in an intestinal Ccl2/Ccr2-dependent manner. Cell Metab. 24, 295–310 (2016).

    Article  CAS  PubMed  Google Scholar 

  57. Glass, L. L. et al. Single-cell RNA-sequencing reveals a distinct population of proglucagon-expressing cells specific to the mouse upper small intestine. Mol. Metab. 6, 1296–1303 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  58. Roberts, G. P. et al. Comparison of human and murine enteroendocrine cells by transcriptomic and peptidomic profiling. Diabetes 68, 1062–1072 (2019).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  59. Oya, M. et al. The G protein-coupled receptor family C group 6 subtype A (GPRC6A) receptor is involved in amino acid-induced glucagon-like peptide-1 secretion from GLUTag cells. J. Biol. Chem. 288, 4513–4521 (2013).

    Article  CAS  PubMed  Google Scholar 

  60. Pi, M. et al. GPRC6A null mice exhibit osteopenia, feminization and metabolic syndrome. PLoS ONE 3, e3858 (2008).

    Article  PubMed  PubMed Central  Google Scholar 

  61. Rudenko, O. et al. The aromatic amino acid sensor GPR142 controls metabolism through balanced regulation of pancreatic and gut hormones. Mol. Metab. 19, 49–64 (2019).

    Article  CAS  PubMed  Google Scholar 

  62. Igarashi, A. et al. Acute oral calcium suppresses food intake through enhanced peptide-YY secretion mediated by the calcium-sensing receptor in rats. J. Nutr. 151, 1320–1328 (2021).

    Article  PubMed  Google Scholar 

  63. Muramatsu, M. et al. Activation of the gut calcium-sensing receptor by peptide agonists reduces rapid elevation of plasma glucose in response to oral glucose load in rats. Am. J. Physiol. Gastrointest. Liver Physiol. 306, G1099–G1107 (2014).

    Article  CAS  PubMed  Google Scholar 

  64. McConnell, E. L., Basit, A. W. & Murdan, S. Measurements of rat and mouse gastrointestinal pH, fluid and lymphoid tissue, and implications for in-vivo experiments. J. Pharm. Pharmacol. 60, 63–70 (2008).

    Article  CAS  PubMed  Google Scholar 

  65. Kalogeris, T. J., Reidelberger, R. D. & Mendel, V. E. Effect of nutrient density and composition of liquid meals on gastric emptying in feeding rats. Am. J. Physiol. 244, R865–R871 (1983).

    CAS  PubMed  Google Scholar 

  66. Duca, F. A., Katebzadeh, S. & Covasa, M. Impaired GLP-1 signaling contributes to reduced sensitivity to duodenal nutrients in obesity-prone rats during high-fat feeding. Obesity (Silver Spring) 23, 2260–2268 (2015).

    Article  CAS  PubMed  Google Scholar 

  67. Zhang, S.-Y. et al. Metformin triggers a kidney GDF15-dependent area postrema axis to regulate food intake and body weight. Cell Metab. 35, 875–886 (2023).

    Article  CAS  PubMed  Google Scholar 

  68. Bauer, P. V. et al. Metformin alters upper small intestinal microbiota that impact a glucose-SGLT1-sensing glucoregulatory pathway. Cell Metab. 27, 101–117 (2018).

    Article  CAS  PubMed  Google Scholar 

  69. Ellacott, K. L. J., Morton, G. J., Woods, S. C., Tso, P. & Schwartz, M. W. Assessment of feeding behavior in laboratory mice. Cell Metab. 12, 10–17 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

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Acknowledgements

R.J.W.L. is supported by an Ontario Graduate Scholarship. D.R.B. is supported by a Canadian Institutes of Health Research (CIHR) graduate scholarship. R.K. is supported by a CIHR graduate scholarship and a Banting and Best Diabetes Centre (BBDC) graduate scholarship. Y.-M.L. was supported by a BBDC-Kangbuk Samsung postdoctoral fellowship. A.G. was supported by a BBDC Charles Hollenberg summer studentship. S.-Y.Z. is supported by a CIHR postdoctoral fellowship. J.L.B. holds grant funds from NSERC-Discovery, BBDC-New Researcher award, Drucker family innovation grant and CIHR. This work was supported by a CIHR grant (no. PJT-183901) to T.K.T.L., who holds a Tier 1 Canada Research Chair in Diabetes and Obesity at the Toronto General Hospital Research Institute and the University of Toronto.

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Author notes

  1. These authors contributed equally: Rosa J. W. Li, Daniel R. Barros.

Authors and Affiliations

  1. Department of Physiology, University of Toronto, Toronto, Ontario, Canada

    Rosa J. W. Li, Daniel R. Barros, Rachel Kuah & Tony K. T. Lam

  2. Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada

    Rosa J. W. Li, Daniel R. Barros, Rachel Kuah, Yu-Mi Lim, Anna Gao, Song-Yang Zhang & Tony K. T. Lam

  3. Medical Research Institute, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea

    Yu-Mi Lim

  4. Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada

    Jacqueline L. Beaudry

  5. Department of Medicine, University of Toronto, Toronto, Ontario, Canada

    Tony K. T. Lam

  6. Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada

    Tony K. T. Lam

  7. Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada

    Tony K. T. Lam

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Contributions

R.J.W.L. and D.R.B. designed and conducted experiments, performed data analysis and wrote the manuscript. R.K., Y.-M.L., A.G., J.L.B. and S.-Y.Z. assisted with experiments. T.K.T.L. supervised the project, designed experiments and edited the manuscript.

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Correspondence to Tony K. T. Lam.

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Nature Metabolism thanks Freddy J. Troost and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Yanina-Yasmin Pesch, in collaboration with the Nature Metabolism team.

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Extended data

Extended Data Fig. 1 Supporting data relating to Fig. 1.

a, Working hypothesis. b,c, Experimental timelines of (b) IVGTT and (c) fasting-refeeding studies. d,e, Food intake upon refeeding of chow rats following USI infusions of (d) Sal (n = 11) or Cas (n = 8) after NPS pre-infusion, or (e) Sal (n = 12) or Cas (n = 12) after 4-AMBA pre-infusion.*p < 0.05, **p < 0.01 determined by two-tailed t-test. Sal, saline; Cas, casein; NPS, NPS2143; 4-AMBA, 4-aminobenzoicacid. Data are presented as mean ± s.e.m.

Source data

Extended Data Fig. 2 Supporting data relating to Fig. 2.

a,b, Pre-experimental (a) bodyweight and (b) cumulative 3-day food intake of chow (n = 64) and HF (n = 27) rats with USI cannulation before refeeding experiments. c,d, Pre-experimental (c) bodyweight and (d) cumulative 3-day food intake of USI chow (n = 36) ad HF (n = 54) USI rats before IVGTT. e,f, Pre-experimental (e) bodyweight and (f) cumulative 3-day food intake of chow (n = 27) and HF (n = 37) USI rats with USI lentiviral (LV) injections before IVGTT studies. g-i, Plasma glucose levels during IVGTT (inset: AUC) of HF rats (g) with USI shMM receiving USI Sal (n = 5) or Cas (n = 7), or (h) no viral injection receiving 4AMBA+Sal (n = 8) or 4AMBA+Cas (n = 8), or (i) with USI shPepT1 receiving USI Sal (n = 7) or Cas (n = 5). j,k, Experimental timeline for collection of blood collection for gut hormone assay in the context of (j) fasting-refeeding or (k) IVGTT studies. l, Plasma levels of GLP1, GIP, and PYY receiving USI Sal (n= 7,6,7) or Cas (n = 8,7,8). *p < 0.05, **p < 0.01 determined by two-tailed t-test or multiple t-tests for IVGTT (g-i). Sal, saline; Cas, casein; 4AMBA, 4-aminobenzoicacid. Data are presented as mean ± s.e.m.

Source data

Extended Data Fig. 3 Supporting data relating to Fig. 3.

a,b, Food intake upon refeeding of chow rats (a) with Ile shMM injection after Ile Sal (n = 9) or Cas (n = 12), or (b) of non-viral injected rats receiving Ile Sal (n = 8) or Cas (n = 10) after 4AMBA pre-infusion. c,d, Pre-experimental (c) bodyweight and (d) cumulative 3-day food intake of chow (n = 46) and HF (n = 24) rats with Ile cannulation before undergoing refeeding experiments. Ile, ileum; Sal, saline; Cas, casein; 4AMBA, 4-aminobenzoicacid. *p < 0.05, **p < 0.01 as determined by two-tailed t-tests. Mann Whitney test is used for non-parametric data sets determined by Shapiro-Wilk test. Data are presented as mean ± s.e.m.

Source data

Extended Data Fig. 4 Supporting data relating to Fig. 4.

a, Plasma glucose levels during IVGTT (inset: AUC) of Ile shCaSR rats receiving Ile Sal (n = 5) or Cas (n = 5). b,c, Pre-experimental (b) bodyweight and (c) cumulative food intake of chow (n = 53) and HF (n = 37) diet rats with Ile and vascular cannulation before undergoing IVGTT studies. d,e, Plasma glucose levels during IVGTT (inset: AUC) of (d) HF rats receiving Ile 4AMBA+Sal (n = 7) or 4AMBA+Cas (n = 6), or (e) of Ile shPepT1-injected HF rats receiving Ile Sal (n = 8) or Cas (n = 7). *p < 0.05, **p < 0.01 as determined by two-tailed t-tests or multiple t-tests for IVGTT (a,d,e). Mann Whitney test is used for non-parametric data sets determined by Shapiro-Wilk test. Ile, ileum; Sal, saline; Cas, casein; 4AMBA, 4-aminobenzoicacid. Data are presented as mean ± s.e.m.

Source data

Extended Data Table 1 Pre-experimental food intake and bodyweight of chow rats that underwent that IVGTT
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Extended Data Table 2 Pre-experimental food intake and bodyweight of chow rats that underwent fasting-refeeding experiments
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Extended Data Table 3 Pre-experimental food intake and bodyweight of HF rats that underwent IVGTT
Full size table
Extended Data Table 4 Pre-experimental food intake and bodyweight of HF rats that underwent fasting-refeeding experiments
Full size table

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Li, R.J.W., Barros, D.R., Kuah, R. et al. Small intestinal CaSR-dependent and CaSR-independent protein sensing regulates feeding and glucose tolerance in rats. Nat Metab 6, 39–49 (2024). https://doi.org/10.1038/s42255-023-00942-4

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