Palmitate activates AMP-activated protein kinase and regulates insulin secretion from beta cells.
AMP-activated protein kinase (AMPK) is an energy sensor that regulates cellular metabolism. Changes in AMPK activity contribute to the regulation of insulin secretion. Epidemiological evidence links the ingestion of saturated fatty acid with hyperinsulinemia. The aim of the present study was to examine the effects of palmitate on beta cell AMPK activity and insulin secretion. Isolated rat islets and MIN6 beta cells were treated acutely (5-60 min) or chronically (24 h) with palmitate. Insulin secretion, AMPK and acetyl CoA carboxylase phosphorylation were assessed. The acute effects of palmitate included AMPK activation and augmentation in insulin secretion. Activation of AMPK by 24h pretreatment with palmitate suppressed glucose-stimulated insulin secretion, but not the response of insulin secretion to combined stimuli of glucose and palmitate. This study demonstrated that palmitate availability affected beta cell AMPK activity. In beta cells, an increase in AMPK activity may be required for fatty acid-induced fatty acid oxidation and prevention of lipotoxicity.
Wang
Xiao
X
Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China.
Zhou
Libin
L
Li
Guo
G
Luo
Tianhong
T
Gu
Yanyun
Y
Qian
Lei
L
Fu
Xuelian
X
Li
Fengying
F
Li
Jiping
J
Luo
Min
M
D055372:AMP-Activated Protein Kinases; D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism*; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism*; D019308:Palmitic Acid / Q000008:administration & dosage*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D007328:Insulin; D009097:Multienzyme Complexes; D019308:Palmitic Acid; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases