Abstract
In the previous paper, it was reported that the cardiac hypertrophy was produced as a parmanent effect of high altitude exposure in mice. The forced exercising test was carried out on mice at sea level produced the cardiac hypertrophy resembling to that mentioned above. Fifty mice of ICR-JCL strain born at sea level were used and randomly divided into four groups; ten for control, and fifteen for test groups in each sex. For 50 days from the 3rd to the 10th week after birth, the exercising groups were loaded daily by the treadmill for mice under the time schedule in which total distance of running was 37, 630m. At the 11th week after birth, electrocardiograms of these mice were recorded and the organ weights and the thickness of ventricular walls were measured. Difference between the control and theexercisinggroupswastestedstatistically(α=0.05)ineachitem.
The results obtained are as follows: 1) The kidney(in both sexes), the spleen(in male), the liver(in both sexes), the brain(in female) and the heart(in female) weights per body weights(0/00) of the exercising group were significantly greater than those of the control group. 2) No significant differneces were recognized in adrenal weights of both groups in both sexes, although adrenal weight increased in mice exposed in high altitude remarkably. 3) The right ventricular walls of the exercising group increased in thickness and the ratio of the right to the left markedly decreased in both sexes. 4) The durations of QRS complex prolonged significantly in the exercising group of both sexes, but no circulatory disorders were found in all individuals. 5) These results demonstrated that the cardiac hypertrophy without dysfunciton was produced by the high altitude exposure and/or by the forced exercise in mice, as a common responce to these conditionings.
