TY - JOUR

T1 - Vascular, but not luminal, activation of FFAR1 (GPR40) stimulates GLP-1 secretion from isolated perfused rat small intestine

AU - Christensen, Louise Wulff

AU - Kuhre, Rune Ehrenreich

AU - Janus, Charlotte

AU - Svendsen, Berit

AU - Holst, Jens Juul

PY - 2015/9/17

Y1 - 2015/9/17

N2 - Glucagon-like peptide 1 (GLP-1) plays a central role in modern treatment of type 2 diabetes (T2DM) in the form of GLP-1 enhancers and GLP-1 mimetics. An alternative treatment strategy is to stimulate endogenous GLP-1 secretion from enteroendocrine L cells using a targeted approach. The G-protein-cou- pled receptor, FFAR1 (previously GPR40), expressed on L cells and activated by long-chain fatty acids (LCFAs) is a potential target. A link between FFAR1 activation and GLP-1 secretion has been demonstrated in cellular models and small-molecule FFAR1 agonists have been developed. In this study, we exam- ined the effect of FFAR1 activation on GLP-1 secretion using isolated, per- fused small intestines from rats, a physiologically relevant model allowing distinction between direct and indirect effects of FFAR1 activation. The endogenous FFAR1 ligand, linoleic acid (LA), and four synthetic FFAR1 ago- nists (TAK-875, AMG 837, AM-1638, and AM-5262) were administered through intraluminal and intra-arterial routes, respectively, and dynamic changes in GLP-1 secretion were evaluated. Vascular administration of 10 mol/L TAK-875, 10 mol/L AMG 837, 1 mol/L and 0.1 mol/L AM-1638, 1 mol/L AM-6252, and 1 mmol/L LA, all significantly increased GLP-1 secretion compared to basal levels (P<0.05), whereas luminal administration of LA and FFAR1 agonists was ineffective. Thus, both natural and small-mole- cule agonists of the FFAR1 receptor appear to require absorption prior to stimulating GLP-1 secretion, indicating that therapies based on activation of nutrient sensing may be more complex than hitherto expected.

AB - Glucagon-like peptide 1 (GLP-1) plays a central role in modern treatment of type 2 diabetes (T2DM) in the form of GLP-1 enhancers and GLP-1 mimetics. An alternative treatment strategy is to stimulate endogenous GLP-1 secretion from enteroendocrine L cells using a targeted approach. The G-protein-cou- pled receptor, FFAR1 (previously GPR40), expressed on L cells and activated by long-chain fatty acids (LCFAs) is a potential target. A link between FFAR1 activation and GLP-1 secretion has been demonstrated in cellular models and small-molecule FFAR1 agonists have been developed. In this study, we exam- ined the effect of FFAR1 activation on GLP-1 secretion using isolated, per- fused small intestines from rats, a physiologically relevant model allowing distinction between direct and indirect effects of FFAR1 activation. The endogenous FFAR1 ligand, linoleic acid (LA), and four synthetic FFAR1 ago- nists (TAK-875, AMG 837, AM-1638, and AM-5262) were administered through intraluminal and intra-arterial routes, respectively, and dynamic changes in GLP-1 secretion were evaluated. Vascular administration of 10 mol/L TAK-875, 10 mol/L AMG 837, 1 mol/L and 0.1 mol/L AM-1638, 1 mol/L AM-6252, and 1 mmol/L LA, all significantly increased GLP-1 secretion compared to basal levels (P<0.05), whereas luminal administration of LA and FFAR1 agonists was ineffective. Thus, both natural and small-mole- cule agonists of the FFAR1 receptor appear to require absorption prior to stimulating GLP-1 secretion, indicating that therapies based on activation of nutrient sensing may be more complex than hitherto expected.

KW - Faculty of Health and Medical Sciences

KW - G-protein-coupled receptor

KW - incretin

KW - long- chain fatty acids

U2 - 10.14814/phy2.12551

DO - 10.14814/phy2.12551

M3 - Journal article

C2 - 26381015

VL - 3

SP - 1

EP - 13

JO - Physiological Reports

JF - Physiological Reports

SN - 2051-817X

IS - 9

M1 - e122551

ER -