Effects of Oolong Tea on Metabolism of Plasma Fat in Mice under Restraint Stress

We investigated the effects of oolong tea on the basic metabolism of plasma lipids in mice under restraint stress. When a lipid emulsion (Intralipid 20%; a lipid emulsion containing 20% soybean oil) was injected intravenously into mice, the restraint stress prolonged the half-life (T1/2) of elimination for plasma triglyceride (TG) from 28.7 to 55.5 min. The elimination rate per minute was 48.2% in stressed mice with the rate in starved control mice as 100%. Therefore, TG metabolism was disrupted by the stress, and the use of TG as an energy source decreased. We found that the metabolism of lipids significantly response to the restrained stress in the present study. Plasma TG was 515.9±29.9 mg/dl 35 min after Intralipid administration in control stressed mice, 478.7±26.7 mg/dl in the stressed group given caffeine 100 mg/kg of body weight, and 418.3±18.4 mg/dl in the stressed group given 1000 mg/kg oolong tea, an improvement by 7.2% and 18.9%, respectively, with the value for the untreated control group. Th...