EFFECT OF VOLUNTARY EXERCISE ON 3'-METHYL-4-DIMETHYLAMINOAZOBENZENE-INDUCED HEPATOMAS IN MALE JC1-WISTAR RATS

The effect of voluntary exercise on 3'-methyl-4-dimethylaminoarobenzen e (3'-Me-DAB)-induced hepatomas was investigated in male Jc1:Wistar ra ts. Beginning at 10 weeks of age, animals were divided into two groups (sedentary and exercise) and housed in individual cages. Food intake and wheel exercise were automatically controlled in the cages of the e xercise group. Body weights were monitored throughout the study. Food availability was controlled in order to equate length and weight gain. From 27 weeks to termination of the study at 62 weeks, all animals we re administered 3'-Me-DAB in the diet at a dose level of 0.0177 g/day/ kg body wt. All animals were sacrificed at 62 weeks of age. The incide nce of hepatomas was significantly lower in the exercise group as comp ared with the sedentary group (0% and 65%, respectively). Liver weight was significantly greater in the exercise group compared with sedenta ry animals without hepatomas. The weight of epididymal fat pads was si gnificantly lower in the exercise group. Serum alkaline phosphatase wa s significantly higher in the exercise group as compared with the sede ntary group. Serum gamma-glutamyl-transpeptidase levels were higher in the sedentary group than in the exercise group. In addition, gamma-gl utamyl-transpeptidase levels were significantly higher in sedentary an imals with hepatomas than in sedentary animals without hepatomas. Thes e results demonstrate that voluntary exercise decreases 3'-Me-DAB-indu ced hepatomas and that this decrease is associated with an increase in serum alkaline phosphatase and a decrease in serum gamma-glutamyl-tra nspeptidase levels.