The effect of fasting time on plasma total cholesterol concentration in Mongolian gerbils.

This study investigated the effect of length of fasting time on plasma total cholesterol response of male Mongolian gerbils (Meriones unguiculatus). Plasma cholesterol levels from fed and fasted gerbils were also compared with those reported for humans under similar metabolic states. Plasma total cholesterol response showed a significant quadratic relationship with time over a 15-hour period. Between 6 and 9 hours of fasting (the time during which plasma triglyceride concentration became relatively constant), the average plasma total cholesterol concentration was 178 mg/dl, compared with a zero hour (fed) cholesterol level of 265 mg/dl. The difference in plasma cholesterol levels observed in fed and fasted gerbils is unlike what has been reported for humans. Results from most human studies show no differences in plasma total cholesterol concentrations for fed and fasted subjects. Failure to consider species differences in metabolic responses may have implications when results from animal experiments are extrapolated to humans.