Abstract
C57BL/6 female mice were fed high fat diets containing different types of carbohydrate
(sucrose or corn starch) and contents of cholesterol (0.03% or 1%) to identify early
metabolic changes leading to increases in leptin levels and eventual insulin resistance.
Under identical dietary fat conditions, type of carbohydrate and cholesterol content
contributed to the timing of leptin increases. Mice fed a high-fat, high-sucrose diet
showed early (4 weeks) and robust increases in circulating insulin and leptin levels
(2-fold and 5-fold, respectively). In contrast, mice fed this diet with added cholesterol
or with sucrose substituted by corn starch led to marked delays (8 - 10 weeks) in
the elevations of insulin and leptin, although body weight gains were nearly identical
among test diet groups. Thus, sucrose in combination with saturated fat played a specific
role in initiating early metabolic changes associated with elevated leptin and insulin
levels. Because leptin levels were most reflective of changes in insulin, our data
support a role for insulin in determining plasma leptin levels in mice.
Key words
Diabetes - Obesity - Sucrose - Fat - Corn Starch - Cholesterol
