INTRODUCTION AND AIM: To clarify the effects of a high fat-diet on insulin secretion from genetically diabetic beta cells, Goto-Kakizaki rats and Wistar rats were subjected to oral glucose tolerance test (OGTT) after 12-week high-fat feeding. METHODOLOGY: We compared Wistar and Goto-Kakizaki (GK) rats fed a high-fat diet (45% fat content) for 12 weeks, measuring insulin secretion and insulin release. RESULTS: Insulin secretion during oral glucose tolerance test (OGTT) was enhanced in high-fat diet-fed Wistar rats (WF) with normal glucose tolerance. Insulin secretion in high-fat diet-fed GK rats (GF) during OGTT also was enhanced together with deteriorated glucose tolerance. Basal insulin release from the isolated perfused pancreas at 3.3 m glucose in WF was comparable to that in normal chow-fed Wistar rats (WN), but basal insulin release in GF was remarkably higher than in normal chow-fed GK rats (GN). Stimulated insulin release induced by 16.7 m glucose was remarkably increased in WF compared with WN. Total insulin release at 16.7 m glucose in both GK rat groups was similar and minimal. CONCLUSION: These results indicate that normal pancreatic beta-cells have the ability to secrete sufficient insulin to compensate for the insulin resistance induced by a high-fat diet. In contrast, glucose metabolism in diabetic rats after high-fat diet deteriorated partly because of insufficient insulin secretion caused by genetic defects and lipotoxicity due to chronically high FFA levels.
INTRODUCTION AND AIM: To clarify the effects of a high fat-diet on insulin secretion from genetically diabetic beta cells, Goto-Kakizaki rats and Wistar rats were subjected to oral glucose tolerance test (OGTT) after 12-week high-fat feeding. METHODOLOGY: We compared Wistar and Goto-Kakizaki (GK) rats fed a high-fat diet (45% fat content) for 12 weeks, measuring insulin secretion and insulin release. RESULTS: Insulin secretion during oral glucose tolerance test (OGTT) was enhanced in high-fat diet-fed Wistar rats (WF) with normal glucose tolerance. Insulin secretion in high-fat diet-fed GK rats (GF) during OGTT also was enhanced together with deteriorated glucose tolerance. Basal insulin release from the isolated perfused pancreas at 3.3 m glucose in WF was comparable to that in normal chow-fed Wistar rats (WN), but basal insulin release in GF was remarkably higher than in normal chow-fed GK rats (GN). Stimulated insulin release induced by 16.7 m glucose was remarkably increased in WF compared with WN. Total insulin release at 16.7 m glucose in both GK rat groups was similar and minimal. CONCLUSION: These results indicate that normal pancreatic beta-cells have the ability to secrete sufficient insulin to compensate for the insulin resistance induced by a high-fat diet. In contrast, glucose metabolism in diabeticrats after high-fat diet deteriorated partly because of insufficient insulin secretion caused by genetic defects and lipotoxicity due to chronically high FFA levels.
Authors: P Matafome; E Nunes; T Louro; C Amaral; J Crisóstomo; L Rodrigues; A R Moedas; P Monteiro; A Cipriano; R Seiça Journal: Naunyn Schmiedebergs Arch Pharmacol Date: 2008-10-21 Impact factor: 3.000