Abstract: ObjectiveTo investigate the changes of expression of uncoupling protein 2(UCP-2)mRNA and unconpling protein 3(UCP-3)mRNA in infant and adult rats treated with repeated fasting/refeeding.MethodsA repeated fasting/refeeding of infant and adult rats model was designed and the rats were fed with a repeated cycle of 1day fasting and 1 day refeeding for 6 weeks.The body weight and Lee's index were measured.Glucose,free fatty acid(FFA)and cholinesterase(CHE)levels,and the expressions of UCP-2 mRNA and UCP-3 mRNA were detected.ResultsCompared to the control(375.36±21.12 g,396±18.14 g),the body weight of infant and adult rats in repeated fasting/refeeding group (243.73±17.66 g,261.12±19.51 g)decreased significantly and the serum glucose levels of adult rats decreased significantly(P<0.05).Compared to the control,serum FFA level of fasting/refeeding rats increased significantly(P<0.05). Conpared to the infant rats,serum CHE level of adult rats increased significantly(P<0.01).Compared to the control,the expression of UCP2 mRNA in white fat tissue(WAT)of infant and adult rats increased significantly(P<0.05).Compared to the control infant rats,the expression of UCP-2 mRNA in WAT of adult control rats decreased significantly(P<0.05). Compared to fasting/refeeding infant rats,the expression of UCP-2 mRNA in WAT of adult rats increased significantly(P<0.05).ConclusionThe repeated fasting/refeeding can increase the expression of UCP2 mRNA in WAT and improve energy metabolism in rats.