抄録
The heart consumes and stores a large amount of fats as its energy source in addition to carbohydrate. It is supposed that other lipases than lipoprotein lipase, which has been investigated so far, are concerned in the hydrolysis of the triglyceride fatty acid reserved in the myocardium. However, few investigations about them have been done. A lipase activity, sensitive to epinephrine, was detected from the rat heart homogenate. Its properties were studied about the optimal pH, the presence of fractions, the effect of fasting, the degree of activity increased by activators, the effect of lipase inhibitors and the effect of β-blocking agent. Methods : Wister strain male albino rats weighed about 2OOg were killed by decapitation. The hearts were removed quickly and rinsed in the ice-cold Krebs-Ringer phosphate buffer. The homogenate was prepared by homogenizing the tissue in 6ml of 0.25 M sucrose solution per gram of tissue in a glass homogenizer. The homogenate was centrifuged at 12, 000 × g for ten minutes at 4°C. The supernatant fluid was taken for the assay of lipolytic activity. The reaction mixture consists of the following ; 0.4 ml of enzyme solution, 0.1 ml of 50 per cent Fatgen (20 per cent sesam oil emulsion), 0.5 ml of 20 per cent extracted albumin (pH 7.0), 0.2 ml of 0.06 M phosphate buffer (pH 6.8) and 0.8 ml of distilled water: Free fatty acid was assayed before and after the one hour incubation at 37°C. Free fatty acid was extracted according to the method of DOLE and determined photometrically by that of MOSINGER.
