Context Exercise training has long been utilized as an adjunct to pharmacotherapy in the management of diabetes. Objectives The effects of a heavy exercise training program on the distribution of insulin, glucagon, somatostatin and pancreatic polypeptide in pancreatic islet cells of diabetic rats was investigated. Animals Forty male Wistar rats. Design The animals were divided into 4 groups: control sedentary, diabetic sedentary, control heavy exercise, and diabetic heavy exercise. Intervention Diabetes was induced with a single injection of streptozotocin (60 mg/kg i.p.). The exercise program included five 60-min sessions per week, speed 18 m/min with a running belt at a 5% incline and began 1 week after the streptozotocin treatment and continued for 12 weeks. Main outcome measure Immunohistochemistry was used to label insulin, glucagon, somatostatin and pancreatic polypeptide in islet cells. Results The percentage of insulin-positive cells was significantly lower in islets from diabetic rats (24.2±2.3%) as compared to the controls (87.5±2.0%). The percentage of glucagon-positive cells was significantly higher in islets from diabetic rats (44.0±1.7%) as compared to the controls (34.7±2.1%). The percentage of pancreatic polypeptide-positive cells was also significantly higher in islets from diabetic rats (20.8±1.6%) as compared to the controls (12.7±1.8%). The percentage of somatostatin-positive cells was not significantly altered in islets from diabetic rats (28.2±2.0%) as compared to the controls (21.9±2.7%). Heavy exercise did not significantly alter insulin, glucagon, pancreatic peptide or somatostatin labeling in either diabetic or control rats. Conclusions Alterations in the distribution of pancreatic hormones in streptozotocin-induced diabetic rats, a model of type 1 diabetes, are not improved with heavy exercise.
Frank Christopher Howarth, Farida Mohammed Abdulla Marzouqi, Amal Mohammed Salem Al Saeedi, Rasheed Shaul Hameed, Ernest Adeghate