J. A. Hebert

Total serum cholesterol and urinary dehydroepiandrosterone in humans

The relationship between urinary excretion of dehydroepiandrosterone (DHEA) and total serum cholesterol was evaluated in an epidemiological study of coronary risk factors. The results of this study show statistically significant negative correlation (r = -0.238; P -0.014) between the urinary excretion of DHEA (mg/g creatinine) and total serum cholesterol. Total serum cholesterol (r = 0.278) and to a lesser extent. DHEA (R = 0.021) were found to be correlated with age. However, it was determined that the correlation between serum cholesterol and urinary DHEA was not attributable to the effect of age, since the partial correlation coefficient between serum cholesterol and urinary DHEA adjusted for age (r = 0.240) was found to be statistically significant (P less than 0.05). Negative but non-significant correlations were also found between urinary excretion of DHEA and many of the accepted risk factors for coronary heart disease.

Metabolic effects of exercise. I. Effect of exercise on serum lipids and lipogenesis in rats.

Summary To evaluate the metabolic effects of exercise, three groups of exercised male rats were compared to their sedentary controls at the end of 10 wk of voluntary exercise in rodent activity cages. Exercised rats consumed more food than sedentary rats but had greater weight gain only at the higher levels of activity. Exercised rats had significantly lower serum triglycerides and higher values of adipose tissue α-glycero-phosphate dehydrogenase activity. At higher levels of physical activity, the exercised rats exhibited larger adrenal glands and lower values of hepatic glucose-6-phosphate dehydrogenase. It is concluded that specific levels of voluntary exercise are needed to achieve specific metabolic effects.

Metabolic effects of exercise. II. Residual metabolic effects of exercise in rats.

Summary This report describes the duration of changes in serum lipids, adrenal weight and hepatic G-6-PD activity in rats following the termination of 10 weeks of voluntary activity in a revolving drum. Exercised rats had lower weight gain, larger adrenal glands, lower serum cholesterol, lower serum triglycerides and lower liver glucoses-phosphate dehydrogenase (G-6-PD) activity than the sedentary controls. The differences between exercise and control rats in adrenal gland weight, body weight and G-6-PD tend to disappear within 3 wk after termination of the exercise. These experiments provide evidence that exercise can affect lipid metabolism and have a beneficial effect on the lowering of serum lipids. It also shows that this effect will persist for up to 3 wk after the exercise is terminated, under the experimental conditions of this study. The authors greatly acknowledge the technical assistance of Mrs. Lillie Bell.