EFFECTS OF DIETARY CALORIE RESTRICTION OR EXERCISE ON THE PI3K AND RAS SIGNALING PATHWAYS IN THE SKIN OF MICE*

Weight control by exercise and dietary calorie restriction (DCR) has been associated with reduced cancer risk, but the underlying mechanisms are not well understood. This study was designed to compare the effects of weight loss by increasing physical activity or decreasing calorie intake on tumor promoter-induced Ras-MAPK and PI3K-Akt pathways. SENCAR mice were randomly assigned to one of the following five groups: ad libitum-fed sedentary control, ad libitum-fed exercise (AL+Exe), exercise but pair-fed at the amount as controls (PF+Exe), 20% DCR, and 20 % DCR plus exercise (DCR+Exe). After 10-wks, body weight and body fat significantly decreased in the groups of DCR