Mitochondrial Swelling and Uncoupling Activity of Long-Chain Fatty Acids

The effect of various fatty acids on the swelling-contraction and oxidative phosphorylation of mitochondria from rat liver and Ehrlich ascites tumor cell have been studied and the results are as follows: 1. The swelling of rat liver mitochondria is induced by fatty acid. The extent of this uncoupling action is in the descending order of myristate, laurate, parlmitate, stearate and behenate in saturated fatty acid and linoleate, linoleneate, richinoleate and oleate in the unsaturated fatty acid. This swelling action is stronger with unsaturated fatty acids than that of saturated ones and cis form is stronger than trans form. 2. The uncoupling oxidative phosphorylation of rat liver mitochondria is also observed with these fatty acids and the activities are proportional to the degree of the swelling action. 3. The degree of swelling of rat liver mitochondria is proportional to the concentration of oleate and is inhibited by anaerobiosis and respiratory inhibitor except amytal. 4. The mitochondria swollen by fatty acid can be recontracted reversibly by ATP, Mg++ and bovine serum albumin. 5. The swelling action of sodium oleate is the strongest on mitochondria from rat liver, followed by those from the liver of Ehrlich ascites tumor bearing mouse, Ehrlich ascites tumor cells and solid Ehrlich tumor cells. 6. Sodium oleate inhibits the incorporation of 32p into ATP, ADP, GTP and UDPG in mitochondria.</p

The effects of high fatty acid on the glucose metabolism of Ehrlich ascites tumor cells

The effects of high fatty acids such as oleic, richinoleic, linoleic, linolenic, palmitic and stearic acids, on the respiration, glycolysis, organic phosphate synthesis of Ehrlich ascites tumor cells, were studied. The unsaturated fatty acids added to the media enhanced the respiration of the tumor cells at the concentration lower than 0.2 mM, after a short incubation period and inhibited the respiration in a high concentration 0.4 mM. The saturated fatty acids did not show such effect. All the fatty acids, both of saturated and unsaturated, effected the increase in lactate formation in tumor cells, especially markedly at higher concentration being accompanied by the WQ increase and RQ around 1. The respiration lowered by the fatty acids was ameliorated by the addition of glucose. The lactate formation from glucose was greatly enhanced by the addition of fatty acids but hardly from pyruvate. The unsaturated high fatty acids proved to have a strong uncoupling action for oxidative phosphorylation. This effect could be recognized slightly in the saturated fatty acids. The addition of high fatty acid resulted in the striking decrease in ATP and ADP with the increase in AMP. With these results the discussion was conducted concerning the specificity of tumor cell related to the glucose and fatty acid metabolism.</p

An apparatus for simultaneous measurement of 90° light scattering, pyridine nucleotide fluorescence and oxygen consumption of mitochondria

An apparatus for simultaneous measurement of 90° light scattering, pyridine nucleotide fluorescence and oxygen consumption of mitochondria was designed and constructed for the purpose to study the mitochondrial structure and function. Oxygen consumption was measured by rotating platinum eleotrode by the modification of Hagihara's method, attached in the cell of the apparatus. Mitochondrial swelling and shrinkage were measured by 90° light scattering at 650mμ. The monochrome light was made by plism monochromator and was led to the cell of the apparatus. Scattered light of 650mμ at 90° was filtered through the filter trasmitting 650mμ, excluding visual and ultra-violet radiation under 600mμ. Then the scattered light was registered by photomultiplier tube 1P22 which is a good choice for measurement of the light near red end of spectrum. Relative reduced pyridine nucleotide concentration was measured by fluorometry. Fluorometer was constructed as follow: For excitation, a bright light at 365mμ line of marcury lamp was isolated from other bright light by passing through the Hitachi interference filter (365mμ) or Corning No. 7-54 (9863) which transmits ultraviolet light and excludes visual radiation above 410mμ and was led to the cell by half mirror at a position of light path between the monochromator for 90° light scattering and the cell. The fluorescence light was passed through the filter of Corning No. 3-73 (3389) which transmits visual radiation at approximately 440mμ. Then the fluorescence intensity in the spectral interval set by the grating monochromator was registered by photomultiplier 1P21 which has good signal-to-noise ratio, and is suitable for measurements of compounds that fluoresence between 350 and 650mμ. The scattered light at 650mμ was not affected by excitation light and fluorescence light, and fluorescence intensity was not by scattered light at 650mμ. The simultaneous measurements of the oxidation-reduction of p ridine nucleotides, the respiration states and the change of 90° light scattering is given as an example of the performance of the present apparatus