Abstract
AIMS: The oral administration of linoleic acid immediately before glucose tolerance test (OGTT) ameliorated postprandial hyperglycemia via GPR120 pathway in normal and type 1 diabetes (T1DM) rats. Linoleic acid could promote inflammatory mediators, but 10-hydroxy-cis-12-octadecenoic acid (HYA) converted from linoleic acid by Lactobacillus plantarum has higher GPR120 agonistic activity without promoting inflammatory mediators. This study examined whether the oral-administration of HYA immediately before OGTT also ameliorated the postprandial hyperglycemia in normal rats and T1DM rats injected with bolus insulin. METHODS: Normal and T1DM male Sprague-Dawley rats received HYA immediately before OGTT. Other T1DM rats were given HYA and Humulin R immediately before OGTT. We measured the concentration of glucose, insulin, glucagon-like peptide 1 (GLP-1) and cholecystokinin in blood before and after OGTT. We also measured the amount of glucose in the gastric tract after OGTT, and the amount of uptake of methyl-α-D-glucopyranoside in CACO-2 cells. RESULTS: Postprandial hyperglycemia was ameliorated by HYA in normal rats, and the postprandial blood glucose levels were slowly elevated by HYA in the T1DM model rats. HYA partially inhibited the uptake of methyl-α-D-glucopyranoside in CACO-2 cells. HYA slowed gastric motility and increased the plasma GLP-1 and cholecystokinin levels in normal rats. HYA also ameliorated the postprandial hyperglycemia in T1DM rats given bolus insulin. CONCLUSION: Oral administration of HYA immediately before OGTT ameliorated postprandial hyperglycemia through inhibition of glucose absorption and slowing of gastric motility in normal rats. Furthermore, this beneficial effect of HYA was also revealed in T1DM rats injected with bolus insulin.