Changes of Lipogenic and Lipolytic Activities Following Repeated Fasting and Refeeding in Rat

Lee, Chang Koo; Kim, Yong Woon

Abstract

BACKGROUND: It is known that repeated fasting and refeeding increase capacity of fat storage in adipose tissue as an adaptive response to fasting. However, the amount of weight gain in fasted/refed animals falls behind the control level in most rodent studies. Because body weight is regulated by the balance between fat storing effect and fat losing mechanism, it is postulated that there is a certain protective mechanism working against body weight gain following repeated cycles of fasting and refeeding.
METHODS
In this study, the adaptive responses to repeated cycles of one-day fasting and one-day refeeding for 42 days(RFR) were investigated in rats.
RESULTS
The RFR rats gained less body weight than controls. LPL mRNA level of RFR rats was significantly increased in white adipose tissue compared to controls. However, mRNA levels of leptin and adiponectin in these rats were also significantly increased in white adipose tissue compared with controls. Moreover, UCP1 expression in the brown adipose tissue was also increased in RFR rats compared to controls.
CONCLUSION
These data indicated that RFR decreased body weight and fat mass despite increased expression of LPL, which resulted from increased expression of leptin, adiponectin, and UCP1 in RFR rats.