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PLoS One. 2013;8(1):e54250. doi: 10.1371/journal.pone.0054250. Epub 2013 Jan 17.

Serotonin receptor 2C and insulin secretion.

Author information

1
State Key Laboratory of Reproductive Medicine and Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, Jiangsu, China.

Abstract

Type 2 diabetes mellitus (T2DM) describes a group of metabolic disorders characterized by defects in insulin secretion and insulin sensitivity. Insulin secretion from pancreatic β-cells is an important factor in the etiology of T2DM, though the complex regulation and mechanisms of insulin secretion from β-cells remains to be fully elucidated. High plasma levels of serotonin (5-hydroxytryptamine; 5-HT) have been reported in T2DM patients, though the potential effect on insulin secretion is unclear. However, it is known that the 5-HT receptor 2C (5-HT(2C)R) agonist, mCPP, decreases plasma insulin concentration in mice. As such, we aimed to investigate the expression of the 5-HT(2C)R in pancreatic islets of diabetic mice and the role of 5-HT(2C)R signaling in insulin secretion from pancreatic β-cells. We found that 5-HT(2C)R expression was significantly increased in pancreatic islets of db/db mice. Furthermore, treatment with a 5-HT(2C)R antagonist (SB242084) increased insulin secretion from pancreatic islets isolated from db/db mice in a dose-dependent manner, but had no effect in islets from control mice. The effect of a 5-HT(2C)R agonist (mCPP) and antagonist (SB242084) were further studied in isolated pancreatic islets from mice and Min-6 cells. We found that mCPP significantly inhibited insulin secretion in Min-6 cells and isolated islets in a dose-dependent manner, which could be reversed by SB242084 or RNA interference against 5-HT(2C)R. We also treated Min-6 cells with palmitic acid for 24 h, and found that the expression of 5-HT(2C)R increased in a dose-dependent manner; furthermore, the inhibition of insulin secretion in Min-6 cells induced by palmitic acid could be reversed by SB242084 or RNA interference against 5-HT(2C)R. Taken together, our data suggests that increased expression of 5-HT(2C)R in pancreatic β-cells might inhibit insulin secretion. This unique observation increases our understanding of T2DM and suggests new avenues for potential treatment.

PMID:
23349838
PMCID:
PMC3547871
DOI:
10.1371/journal.pone.0054250
[Indexed for MEDLINE]
Free PMC Article

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