Effect of exercise on the responses of rats to DDT.

Two groups of 30 male weanling rats were maintained on a nutritionally adequate diet containing 45% carbohydrate, 16% fat, and 29% protein with or without 1 ppm added DDT. At 100 days of age the two groups were subjected to an oral glucose tolerance test. The groups were then subdivided and half of each group was forced to run 1/16 mi/30 min-day on a treadmill. At 190 days of age the glucose tolerance test was repeated. The animals were killed at 200 days of age, and the lipid content of the serum, liver, and carcass was determined. Serum insulin levels and the DDT levels in the adipose tissue reflected the DDT content of the diet, and no differences in these levels were demonstrated with the addition of the exercise treatment. DDT treatment resulted in lower serum and liver cholesterol and serum insulin levels in sedentary rats. Exercise lowered liver cholesterol and serum insulin in non-DDT-treated rats. When both treatments were imposed, serum insulin cholesterol levels rose. Significant DDT-exercise interaction effects were observed on the glucose tolerance, serum and liver cholesterol, and serum insulin levels.