Open AccessFree fatty acid receptors, G protein‐coupled receptor 120 and G protein‐coupled receptor 40, are essential for oil‐induced gastric inhibitory polypeptide secretion
Author(s) -
Sankoda Akiko,
Harada Norio,
Kato Tomoko,
Ikeguchi Eri,
Iwasaki Kanako,
Yamane Shunsuke,
Murata Yuki,
Hirasawa Akira,
Inagaki Nobuya
Publication year - 2019
Publication title -
journal of diabetes investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.089
H-Index - 50
eISSN - 2040-1124
pISSN - 2040-1116
DOI - 10.1111/jdi.13059
Subject(s) - incretin , gastric inhibitory polypeptide , endocrinology , enteroendocrine cell , medicine , receptor , secretion , biology , chemistry , hormone , diabetes mellitus , endocrine system , type 2 diabetes , glucagon
Aims/Introduction Incretin hormone glucose‐dependent insulinotropic polypeptide/gastric inhibitory polypeptide ( GIP ) plays a key role in high‐fat diet‐induced obesity and insulin resistance. GIP is strongly secreted from enteroendocrine K cells by oil ingestion. G protein‐coupled receptor (GPR) 120 and GPR 40 are two major receptors for long chain fatty acids, and are expressed in enteroendocrine K cells. In the present study, we investigated the effect of the two receptors on oil‐induced GIP secretion using GPR 120‐ and GPR 40‐double knockout ( DKO ) mice. Materials and Methods Global knockout mice of GPR 120 and GPR 40 were crossbred to generate DKO mice. Oral glucose tolerance test and oral corn oil tolerance test were carried out. For analysis of the number of K cells and gene expression in K cells, DKO mice were crossbred with GIP ‐green fluorescent protein knock‐in mice in which visualization and isolation of K cells can be achieved. Results Double knockout mice showed normal glucose‐induced GIP secretion, but no GIP secretion by oil. We then investigated the number of K cells and gene characteristics in K cells isolated from GIP ‐green fluorescent protein knock‐in mice. Deficiency of both receptors did not affect the number of K cells in the small intestine or expression of GIP messenger ribonucleic acid in K cells. Furthermore, there was no significant difference in the expression of the genes associated with lipid absorption or GIP secretion in K cells between wild‐type and DKO mice. Conclusions Oil‐induced GIP secretion is triggered by the two major fatty acid receptors, GPR 120 and GPR 40, without changing K‐cell number or K‐cell characteristics.