text: Glucose-stimulated insulin secretion: Effects of high-fat diet and acute stress.
  One of the major topics in modern societies is the study of relationships between diet, stress and incidence of metabolic disorders. This study aimed to investigate possible impairment in glucose-stimulated insulin secretion induced by a high-fat (cow intra-abdominal fat) diet in response to acute stress. Male Wistar rats were divided into high-fat and normal diet groups and each group was further divided into stress and control subgroups. Stress was induced by a communication box. Plasma levels of glucose, insulin and corticosterone were measured in both diet groups. Glucose tolerance, homeostasis model assessment of insulin resistance (HOMA-IR) index, glucose-stimulated insulin secretion from isolated islets, food and energy intake as well as body weight were also evaluated. In the normal diet group, physical stress increased plasma glucose concentrations. In both diet groups, plasma corticosterone levels increased after stress. HOMA-IR index decreased in high-fat fed rats. Food intake decreased while energy intake increased in the high-fat diet rats. Body weight in both diet groups increased in a similar manner. The high-fat diet did not affect insulin secretion; however, stress decreased insulin secretion from isolated islets of both diet groups. Only in the high fat diet group did physical stress increase insulin secretion at 16.7 mM glucose. The cow intra-abdominal fat, did not affect either plasma glucose and insulin concentrations or glucose-induced insulin secretion. Interestingly, it seems that the high-fat diet enabled the islets of the physically stressed rats to secrete more insulin in response to high glucose concentrations.