The Natural PPAR Agonist Linoleic Acid Stimulated Insulin Release in Rat Pancreas

抄録

Free fatty acids play an important role in regulating animal insulin secretion response. Acute elevated free fatty acids increased animal insulin secretion and glucose-stimulated insulin secretion. In the present study, we perfused rat pancreas to explore the effect of unsaturated fatty acids on insulin secretion. The results showed that linoleic acid, γ-linolenic acid, and arachidonic acid significantly stimulated insulin secretion. Glucose (10 mM) alone induced a biphasic insulin secretion response. The peak effluent insulin concentrations over the baseline were 444% and 800% increase in the first and second insulin secretion phase, respectively. By comparing the percentage increases, arachidonic acid, γ-linolenic acid, or linoleic acid increased glucose-induced insulin release by 555% and 934%, 522% and 995% and 463% and 1,105% in the first and second insulin secretion phase, respectively. However, the percentage increases of insulin secretion were significantly decreased to 402% and 564% in the first and second phase in the rat fed with high-fat diet for 13 weeks. Linoleic acid alone stimulated a 391% increase of the baseline in the peak insulin concentration in the rat fed with a normal diet. The peak insulin concentration was significantly decreased to183% in the rats fed with a long-term high-fat diet. All the results suggested that unsaturated fatty acids stimulated insulin secretion and additively increased glucose-induced insulin secretion in the perfused rat pancreas. However, the rat fed with a high fat diet decreased linoleic acid-induced insulin secretion response.