Metabolism of rat-liver cell suspensions. 1. General properties of isolated cells and occurrence of the citric acid cycle.

Animals. Male rats (230-270g.) of the Wistar albino strain were supplied by the Animal Department, University of Otago Medical School. Enzymes and cofactors. Alcohol dehydrogenase, lactate dehydrogenase and malate dehydrogenase (analytical reagent grade) were obtained from C. F. Boehringer und Soehne G.m.b.H., Mannheim, Germany; glucose 6phosphate dehydrogenase, NADI, NADH, NADP+, NADPH and cytochrome c were from Sigma Chemical Co., St Louis, Mo., U.S.A. "4C-labelled compounds. [2,3-14C1JSuccinic acid and sodium [3-14C]pyruvate were obtained from The Radiochemical Centre, Amersham, Bucks. Chemicals. Sodium acetoacetate was prepared by the method of Krebs & Eggleston (1945) and standardized according to Edson (1935). Sodium DL-fl-hydroxybutyrate was obtained from British Drug Houses Ltd., Poole, Dorset, L-malic acid from California Corp. for Biochemical Research, Los Angeles, Calif.,U.S.A., and palmitic acid and stearic acid (chromatographically pure) from Mann Research Laboratories Inc., New York, U.S.A. Solutions of palmitate or stearate were prepared by dissolving the acids in ethanol, adding a slight excess of KOH or NaOH, evaporating to dryness in vacuo, dissolving the salt in water and adjusting the pH to 7-0. Potassium pyruvate was prepared by neutralizing redistilled pyruvic acid with KHCO3 and standardized by the method of Long (1942). 2,5-Diphenyloxazole was obtained from British Drug Houses Ltd.; p-bis-(5-phenyloxazol-2-yl)benzene and 1-OM-hyamine hydroxide [(p-di-isobutyleresoxyethoxyethyl)dimethylbenzylammonium hydroxide] in methanolic solution were obtained from Nuclear Enterprises, Winnipeg, Canada.