EFFECTS OF FOOD RESTRICTION AND EXERCISE TRAINING ON MITOGEN RESPONSEOF SPLENIC LYMPHOCYTES IN OTSUKA LONG-EVANS TOKUSHIMA FATTY (OLETF) RATS, A MODEL OF SPONTANEOUS NON-INSULIN-DEPENDENT DIABETES-MELLITUS (NIDDM)

We investigated whether mitogen response is impaired in Otsuka Long-Ev ans Tokushima Fatty (OLETF) rats, and the effect of exercise training and food restriction on mitogen response of their splenocytes. OLETF r ats were divided into the following groups at the age of 16 weeks; sed entary, exercise-trained and food-restricted (70% of the food : intake in sedentary mts). Both exercise training and food restriction signif icantly suppressed plasma level of glucose, and serum levels of trigly cerides and cholesterol. In addition, plasma level of insulin was sign ificantly increased by both exercise training and food restriction. Mi togen response of splenocytes showed a marked decrease in OLETF rats c ompared to that of non-diabetic rats (Long-Evans Tokushima Otsuka; LET O), especially in PHA stimulation. Although both exercise training and food restriction did significantly improve the development of diabete s mellitus in OLETF rats, the decreased mitogen response of splenocyte s was not improved. In particular, mitogen responses of splenocytes wi th PHA and Con A were further suppressed by food restriction. These re sults suggest that food restriction and exercise training do not have beneficial effects on decreased cellular immune function in NIDDM rats , whereas they improved the state of NIDDM. (C) 1998 Elsevier Science Inc.