1. Pharmacology, Physiology, and Mechanisms of Incretin Hormone Action
Jonathan E. Campbell, Daniel J. Drucker 
Cell Metabolism 
Volume 17, Issue 6, Pages (June 2013)
DOI: /j.cmet
Copyright © 2013 Elsevier Inc. Terms and Conditions

2. Figure 1 Direct Pharmacological Actions of GLP-1R Agonists
GLP-1R agonists act directly via the GLP-1R on pancreatic islets, heart, intestine, subpopulations of immune cells, kidney, and brain.
Cell Metabolism  , DOI: ( /j.cmet )
Copyright © 2013 Elsevier Inc. Terms and Conditions

3. Figure 2 Indirect Pharmacological Effects of GLP-1R Agonists
Activation of GLP-1R signaling pathways in the brain leads to biological actions in the liver, adipose, and gastrointestinal tract.
Cell Metabolism  , DOI: ( /j.cmet )
Copyright © 2013 Elsevier Inc. Terms and Conditions

4. Figure 3 Physiological Roles of Endogenous GLP-1
The biological actions of GLP-1 as revealed by loss-of-function studies utilizing Glp1r−/− mice or antagonists of the GLP-1R are shown and summarized in the accompanying table.
Cell Metabolism  , DOI: ( /j.cmet )
Copyright © 2013 Elsevier Inc. Terms and Conditions

5. Figure 4 GLP-1 Signal Transduction Pathways in the Pancreatic β Cell
Recent studies delineating roles for β-arrestin-1, β-catenin, and IGF-1R signaling in the effects of GLP-1 on insulin secretion, β cell growth, and function are illustrated.
Cell Metabolism  , DOI: ( /j.cmet )
Copyright © 2013 Elsevier Inc. Terms and Conditions

6. Figure 5 Biological Actions of GIP
The direct and indirect actions of GIP on target tissues are illustrated.
Cell Metabolism  , DOI: ( /j.cmet )
Copyright © 2013 Elsevier Inc. Terms and Conditions