| First Author | Zitzer H | Year | 2006 |
| Journal | Endocrinology | Volume | 147 |
| Issue | 8 | Pages | 3898-905 |
| PubMed ID | 16644917 | Mgi Jnum | J:111676 |
| Mgi Id | MGI:3654717 | Doi | 10.1210/en.2005-1483 |
| Citation | Zitzer H, et al. (2006) Sterol regulatory element-binding protein 1 mediates liver X receptor-beta-induced increases in insulin secretion and insulin messenger ribonucleic acid levels. Endocrinology 147(8):3898-905 |
| abstractText | Liver X receptors (LXRalpha and LXRbeta) regulate glucose and lipid metabolism. Pancreatic beta-cells and INS-1E insulinoma cells express only the LXRbeta isoform. Activation of LXRbeta with the synthetic agonist T0901317 increased glucose-induced insulin secretion and insulin content, whereas deletion of the receptor in LXRbeta knockout mice severely blunted insulin secretion. Analysis of gene expression in LXR agonist-treated INS-1E cells and islets from LXRbeta-deficient mice revealed that LXRbeta positively regulated expression of ATP-binding cassette transporter A1 (ABCA1), sterol regulatory element-binding protein 1 (SREBP-1), insulin, PDX-1, glucokinase, and glucose transporter 2 (Glut2). Down-regulation of SREBP-1 expression with the specific small interfering RNA blocked basal and LXRbeta-induced expression of pancreatic duodenal homeobox 1 (PDX-1), insulin, and Glut2 genes. SREBP-1 small interfering RNA also prevented an increase in insulin secretion and insulin content induced by T0901317. Moreover, 5-(tetradecyloxy)-2-furoic acid, an inhibitor of the SREBP-1 target gene acetyl-coenzyme A carboxylase, blocked T0901317-induced stimulation of insulin secretion. In conclusion, activation of LXRbeta in pancreatic beta-cells increases insulin secretion and insulin mRNA expression via SREBP-1-regulated pathway. These data support the role of LXRbeta, SREBP-1, and cataplerosis/anaplerosis pathways in the control of insulin secretion in pancreatic beta-cells. |
