Horm Metab Res 2011; 43(11): 766-773
DOI: 10.1055/s-0031-1287793
Original Basic
© Georg Thieme Verlag KG Stuttgart · New York

Mechanisms of p-Methoxycinnamic Acid-induced Increase in Insulin Secretion

S. Adisakwattana
1   Department of Pharmacology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
,
W. H. Hsu
2   Department of Biomedical Sciences, Iowa State University, Ames, Iowa, USA
,
S. Yibchok-anun
1   Department of Pharmacology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
› Author Affiliations
Further Information

Publication History

received28 May 2011

accepted 29 August 2011

Publication Date:
18 October 2011 (online)

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Abstract

p-Methoxycinnamic acid (p-MCA) is a cinnamic acid derivative that shows various pharmacologic actions such as hepatoprotective and antihyperglycemic activities. The present study was to elucidate the mechanisms by which p-MCA increases [Ca2+]i and insulin secretion in INS-1 cells. p-MCA (100 μM) increased [Ca2+]i in INS-1 cells. The p-MCA-induced insulin secretion and rise in [Ca2+]i were markedly inhibited in the absence of extracellular Ca2+ or in the presence of an L-type Ca2+ channel blocker nimodipine. These results suggested that p-MCA increased Ca2+ influx via the L-type Ca2+ channels. Diazoxide, an ATP-sensitive K+ channel opener, did not alter p-MCA-induced insulin secretion, nor [Ca2+]i response. In addition, p-MCA enhanced glucose-, glibenclamide-induced insulin secretion whereas it also potentiated the increase in insulin secretion induced by arginine, and Bay K 8644, an L-type Ca2+ channel agonist. Taken together, our results suggest that p-MCA stimulated insulin secretion from pancreatic β-cells by increasing Ca2+ influx via the L-type Ca2+ channels, but not through the closure of ATP-sensitive K+ channels.