Metformin activates a duodenal Ampk–dependent pathway to lower hepatic glucose production in rats


  • A Corrigendum to this article was published on 04 February 2016


Metformin is a first-line therapeutic option for the treatment of type 2 diabetes, even though its underlying mechanisms of action are relatively unclear1,2,3,4,5,6. Metformin lowers blood glucose levels by inhibiting hepatic glucose production (HGP), an effect originally postulated to be due to a hepatic AMP-activated protein kinase (AMPK)-dependent mechanism5,6. However, studies have questioned the contribution of hepatic AMPK to the effects of metformin on lowering hyperglycemia1,3,4, and a gut–brain–liver axis that mediates intestinal nutrient- and hormone-induced lowering of HGP has been identified7. Thus, it is possible that metformin affects HGP through this inter-organ crosstalk. Here we show that intraduodenal infusion of metformin for 50 min activated duodenal mucosal Ampk and lowered HGP in a rat 3 d high fat diet (HFD)-induced model of insulin resistance. Inhibition of duodenal Ampk negated the HGP-lowering effect of intraduodenal metformin, and both duodenal glucagon-like peptide-1 receptor (Glp-1r)–protein kinase A (Pka) signaling and a neuronal-mediated gut–brain–liver pathway were required for metformin to lower HGP. Preabsorptive metformin also lowered HGP in rat models of 28 d HFD–induced obesity and insulin resistance and nicotinamide (NA)–streptozotocin (STZ)–HFD-induced type 2 diabetes. In an unclamped setting, inhibition of duodenal Ampk reduced the glucose-lowering effects of a bolus metformin treatment in rat models of diabetes. These findings show that, in rat models of both obesity and diabetes, metformin activates a previously unappreciated duodenal Ampk–dependent pathway to lower HGP and plasma glucose levels.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Intraduodenal metformin infusion activates duodenal Ampk and lowers HGP in the preabsorptive state.
Figure 2: A duodenal AMPK–GLP-1R–PKA signaling pathway is required for metformin to lower HGP.
Figure 3: A gut–brain–liver neuronal axis is required for the HGP-lowering effect of metformin.
Figure 4: Intraduodenal infusion of metformin lowers HGP in obese and diabetic rats, and the overall acute glucose-lowering effect of a bolus intragastric treatment of metformin is dependent on duodenal Ampk signaling.

Change history

  • 07 May 2015

     In the version of this article initially published, we incorrectly reported the value for the particles per milliliter of Ad-dn-AMPK (D157A) used in the study. It was 3.1 × 10–9 PFU ml–1 and not 1.1 × 10–13 PFU ml–1 as originally reported. The errors have been corrected in the HTML and PDF versions of the article.


  1. 1

    Foretz, M. et al. Metformin inhibits hepatic gluconeogenesis in mice independently of the LKB1/AMPK pathway via a decrease in hepatic energy state. J. Clin. Invest. 120, 2355–2369 (2010).

    CAS  Article  Google Scholar 

  2. 2

    Fullerton, M.D. et al. Single phosphorylation sites in Acc1 and Acc2 regulate lipid homeostasis and the insulin-sensitizing effects of metformin. Nat. Med. 19, 1649–1654 (2013).

    CAS  Article  Google Scholar 

  3. 3

    Madiraju, A.K. et al. Metformin suppresses gluconeogenesis by inhibiting mitochondrial glycerophosphate dehydrogenase. Nature 510, 542–546 (2014).

    CAS  Article  Google Scholar 

  4. 4

    Miller, R.A. et al. Biguanides suppress hepatic glucagon signalling by decreasing production of cyclic AMP. Nature 494, 256–260 (2013).

    CAS  Article  Google Scholar 

  5. 5

    Shaw, R.J. et al. The kinase LKB1 mediates glucose homeostasis in liver and therapeutic effects of metformin. Science 310, 1642–1646 (2005).

    CAS  Article  Google Scholar 

  6. 6

    Zhou, G. et al. Role of AMP-activated protein kinase in mechanism of metformin action. J. Clin. Invest. 108, 1167–1174 (2001).

    CAS  Article  Google Scholar 

  7. 7

    Lam, T.K. Neuronal regulation of homeostasis by nutrient sensing. Nat. Med. 16, 392–395 (2010).

    CAS  Article  Google Scholar 

  8. 8

    Taylor, S.I. Deconstructing type 2 diabetes. Cell 97, 9–12 (1999).

    CAS  Article  Google Scholar 

  9. 9

    Hundal, R.S. et al. Mechanism by which metformin reduces glucose production in type 2 diabetes. Diabetes 49, 2063–2069 (2000).

    CAS  Article  Google Scholar 

  10. 10

    Radziuk, J., Zhang, Z., Wiernsperger, N. & Pye, S. Effects of metformin on lactate uptake and gluconeogenesis in the perfused rat liver. Diabetes 46, 1406–1413 (1997).

    CAS  Article  Google Scholar 

  11. 11

    Stumvoll, M., Nurjhan, N., Perriello, G., Dailey, G. & Gerich, J.E. Metabolic effects of metformin in non-insulin-dependent diabetes mellitus. N. Engl. J. Med. 333, 550–554 (1995).

    CAS  Article  Google Scholar 

  12. 12

    Salpeter, S.R., Buckley, N.S., Kahn, J.A. & Salpeter, E.E. Meta-analysis: metformin treatment in persons at risk for diabetes mellitus. Am. J. Med. 121, 149 e2–157 e2 (2008).

    CAS  Article  Google Scholar 

  13. 13

    Owen, M.R., Doran, E. & Halestrap, A.P. Evidence that metformin exerts its anti-diabetic effects through inhibition of complex 1 of the mitochondrial respiratory chain. Biochem. J. 348, 607–614 (2000).

    CAS  Article  Google Scholar 

  14. 14

    Hawley, S.A. et al. Use of cells expressing gamma subunit variants to identify diverse mechanisms of AMPK activation. Cell Metab. 11, 554–565 (2010).

    CAS  Article  Google Scholar 

  15. 15

    Wang, P.Y. et al. Upper intestinal lipids trigger a gut–brain–liver axis to regulate glucose production. Nature 452, 1012–1016 (2008).

    CAS  Article  Google Scholar 

  16. 16

    Cheung, G.W., Kokorovic, A., Lam, C.K., Chari, M. & Lam, T.K. Intestinal cholecystokinin controls glucose production through a neuronal network. Cell Metab. 10, 99–109 (2009).

    CAS  Article  Google Scholar 

  17. 17

    Rasmussen, B.A. et al. Jejunal leptin-PI3K signaling lowers glucose production. Cell Metab. 19, 155–161 (2014).

    CAS  Article  Google Scholar 

  18. 18

    Breen, D.M. et al. Jejunal nutrient sensing is required for duodenal-jejunal bypass surgery to rapidly lower glucose concentrations in uncontrolled diabetes. Nat. Med. 18, 950–955 (2012).

    CAS  Article  Google Scholar 

  19. 19

    Stepensky, D., Friedman, M., Raz, I. & Hoffman, A. Pharmacokinetic-pharmacodynamic analysis of the glucose-lowering effect of metformin in diabetic rats reveals first-pass pharmacodynamic effect. Drug Metab. Dispos. 30, 861–868 (2002).

    CAS  Article  Google Scholar 

  20. 20

    Maida, A., Lamont, B.J., Cao, X. & Drucker, D.J. Metformin regulates the incretin receptor axis via a pathway dependent on peroxisome proliferator-activated receptor-alpha in mice. Diabetologia 54, 339–349 (2011).

    CAS  Article  Google Scholar 

  21. 21

    Shin, N.R. et al. An increase in the Akkermansia spp. population induced by metformin treatment improves glucose homeostasis in diet-induced obese mice. Gut 63, 727–735 (2014).

    CAS  Article  Google Scholar 

  22. 22

    Vardarli, I., Arndt, E., Deacon, C.F., Holst, J.J. & Nauck, M.A. Effects of sitagliptin and metformin treatment on incretin hormone and insulin secretory responses to oral and ″isoglycemic″ intravenous glucose. Diabetes 63, 663–674 (2014).

    CAS  Article  Google Scholar 

  23. 23

    Harmel, E. et al. AMPK in the small intestine in normal and pathophysiological conditions. Endocrinology 155, 873–888 (2014).

    Article  Google Scholar 

  24. 24

    Bain, J. et al. The selectivity of protein kinase inhibitors: a further update. Biochem. J. 408, 297–315 (2007).

    CAS  Article  Google Scholar 

  25. 25

    He, G. et al. AMP-activated protein kinase induces p53 by phosphorylating MDMX and inhibiting its activity. Mol. Cell. Biol. 34, 148–157 (2014).

    Article  Google Scholar 

  26. 26

    Rasmussen, B.A. et al. Duodenal activation of cAMP-dependent protein kinase induces vagal afferent firing and lowers glucose production in rats. Gastroenterology 142, 834 e3–843.e3 (2012).

    CAS  Article  Google Scholar 

  27. 27

    Richards, P. et al. Identification and characterization of GLP-1 receptor-expressing cells using a new transgenic mouse model. Diabetes 63, 1224–1233 (2014).

    CAS  Article  Google Scholar 

  28. 28

    Yusta, B. et al. GLP-1 receptor activation improves beta cell function and survival following induction of endoplasmic reticulum stress. Cell Metab. 4, 391–406 (2006).

    CAS  Article  Google Scholar 

  29. 29

    Samuel, V.T. et al. Fasting hyperglycemia is not associated with increased expression of PEPCK or G6Pc in patients with Type 2 Diabetes. Proc. Natl. Acad. Sci. USA 106, 12121–12126 (2009).

    CAS  Article  Google Scholar 

  30. 30

    Viollet, B. et al. Cellular and molecular mechanisms of metformin: an overview. Clin. Sci. (Lond.) 122, 253–270 (2012).

    CAS  Article  Google Scholar 

  31. 31

    Shackelford, D.B. et al. LKB1 inactivation dictates therapeutic response of non-small cell lung cancer to the metabolism drug phenformin. Cancer Cell 23, 143–158 (2013).

    CAS  Article  Google Scholar 

  32. 32

    Pollak, M. Overcoming drug development bottlenecks with repurposing: repurposing biguanides to target energy metabolism for cancer treatment. Nat. Med. 20, 591–593 (2014).

    CAS  Article  Google Scholar 

  33. 33

    Martin-Montalvo, A. et al. Metformin improves healthspan and lifespan in mice. Nat. Commun. 4, 2192 (2013).

    Article  Google Scholar 

  34. 34

    Wilcock, C. & Bailey, C.J. Accumulation of metformin by tissues of the normal and diabetic mouse. Xenobiotica 24, 49–57 (1994).

    CAS  Article  Google Scholar 

  35. 35

    Habib, A.M. et al. Overlap of endocrine hormone expression in the mouse intestine revealed by transcriptional profiling and flow cytometry. Endocrinology 153, 3054–3065 (2012).

    CAS  Article  Google Scholar 

  36. 36

    Mulherin, A.J. et al. Mechanisms underlying metformin-induced secretion of glucagon-like peptide-1 from the intestinal L cell. Endocrinology 152, 4610–4619 (2011).

    CAS  Article  Google Scholar 

  37. 37

    Ono, H. et al. Activation of hypothalamic S6 kinase mediates diet-induced hepatic insulin resistance in rats. J. Clin. Invest. 118, 2959–2968 (2008).

    CAS  PubMed  PubMed Central  Google Scholar 

  38. 38

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

    CAS  Article  Google Scholar 

  39. 39

    Filippi, B.M., Yang, C.S., Tang, C. & Lam, T.K. Insulin activates Erk1/2 signaling in the dorsal vagal complex to inhibit glucose production. Cell Metab. 16, 500–510 (2012).

    CAS  Article  Google Scholar 

  40. 40

    Kokorovic, A. et al. Duodenal mucosal protein kinase C-delta regulates glucose production in rats. Gastroenterology 141, 1720–1727 (2011).

    CAS  Article  Google Scholar 

  41. 41

    da Silva Xavier, G. et al. Role for AMP-activated protein kinase in glucose-stimulated insulin secretion and preproinsulin gene expression. Biochem. J. 371, 761–774 (2003).

    CAS  Article  Google Scholar 

  42. 42

    Choi, Y.H., Kim, S.G. & Lee, M.G. Dose-independent pharmacokinetics of metformin in rats: hepatic and gastrointestinal first-pass effects. J. Pharm. Sci. 95, 2543–2552 (2006).

    CAS  Article  Google Scholar 

  43. 43

    Graham, G.G. et al. Clinical pharmacokinetics of metformin. Clin. Pharmacokinet. 50, 81–98 (2011).

    CAS  Article  Google Scholar 

  44. 44

    Sakamoto, K. et al. Deficiency of LKB1 in skeletal muscle prevents AMPK activation and glucose uptake during contraction. EMBO J. 24, 1810–1820 (2005).

    CAS  Article  Google Scholar 

  45. 45

    Dale, S., Wilson, W.A., Edelman, A.M. & Hardie, D.G. Similar substrate recognition motifs for mammalian Amp-activated protein kinase, higher-plant HMG-CoA reductase kinase-A, yeast SNF1, and mammalian calmodulin-dependent protein kinase I. FEBS Lett. 361, 191–195 (1995).

    CAS  Article  Google Scholar 

Download references


The authors are grateful to E. Burdett for technical assistance. This work is supported by a research grant from the Canadian Institute of Health Research (MOP-82701 to T.T.K.L.). F.A.D. is a Banting Fellow. B.A.R. is supported by a Canadian Institute of Health Research Doctoral Vanier Canada scholarship. C.D.C. is supported by a Banting and Best Diabetes Centre graduate studentship. M.Z.-T. is supported by a Banting and Best Diabetes Centre graduate studentship. G.A.R. is supported by the Wellcome Trust Senior Investigator (WT098424AIA), the Medical Research Council Programme (MR/J0003042/1), the Diabetes UK Project Grant (11/0004210) and Royal Society Wolfson Research Merit awards. T.K.T.L. holds the John Kitson McIvor (1915–1942) Endowed Chair in Diabetes Research and the Canada Research Chair in Obesity at the Toronto General Research Institute and the University of Toronto.

Author information




F.A.D. conducted and designed experiments, performed data analyses and wrote the manuscript. B.A.R., C.D.C., M.Z.-T. and B.M.F. assisted with experiments. G.A.R. provided the adenovirus expressing dn-Ampk. T.K.T.L. supervised the project, designed experiments and edited the manuscript.

Corresponding author

Correspondence to Tony K T Lam.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Text and Figures

Supplementary Tables 1–2 and Supplementary Figures 1–4. (PDF 670 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Duca, F., Côté, C., Rasmussen, B. et al. Metformin activates a duodenal Ampk–dependent pathway to lower hepatic glucose production in rats. Nat Med 21, 506–511 (2015).

Download citation

Further reading