Tianeptine, a new tricyclic antidepressant metabolized by beta-oxidation of its heptanoic side chain, inhibits the mitochondrial oxidation of medium and short chain fatty acids in mice.

Tianeptine is a new tricyclic antidepressant which is metabolized mainly by beta-oxidation of its heptanoic side chain. We determined the effects of tianeptine on the mitochondrial oxidation of natural fatty acids in mice. In vitro, tianeptine (0.5 mM) inhibited by only 32% the formation of beta-oxidation products from [1-14C]palmitic acid by hepatic mitochondria, but inhibited by 71% that from [1-14C]octanoic acid and by 51% that from [1-14C]butyric acid. The activity of the tricarboxylic acid cycle, assessed as the in vitro formation of [14C]CO2 from [1-14C]acetylcoenzyme A was decreased by 51% in the presence of tianeptine (0.5 mM). The inhibition of both beta-oxidation and the tricarboxylic acid cycle appeared reversible in mitochondria from mice exposed to tianeptine in vivo but incubated in vitro without tianeptine. In vivo, administration of tianeptine (0.0625 mmol/kg i.p.), decreased by 53 and 58%, respectively, the formation of [14C]CO2 from [1-14C]octanoic acid and [1-14C]butyric acid, but did not significantly decrease that from [1-14C]palmitic acid. After administration of high doses of tianeptine, however, formation of [14C]CO2 from [1-14C]palmitic acid became inhibited as well, transiently after 0.25 mmol/kg and durably (greater than 24 hr) after 0.75 mmol/kg i.p. Hepatic triglycerides were increased 24 hr after administration of 0.75 mmol/kg i.p. of tianeptine, but not after 0.25 mmol/kg i.p. Microvesicular steatosis of the liver was observed in some mice after 0.75 mmol/kg i.p., but not after 0.5 mmol/kg i.p. We conclude that tianeptine inhibits the oxidation of medium- and short-chain fatty acids in mice. Microvesicular steatosis, however, requires very large doses in mice (0.75 mmol/kg i.p., i.e. 600-times the oral dose in humans), and is therefore unlikely to occur in humans.

Biochemical toxicology of argemone alkaloids. III. Effect on lipid peroxidation in different subcellular fractions of the liver.

Consumption of edible oils contaminated with Argemone mexicana seed oil causes various toxic manifestations. In this investigation the in vivo effect of argemone oil on NADPH-dependent enzymatic and Fe2+-, Fe2+/ADP- or ascorbic acid-dependent non-enzymatic hepato-subcellular lipid peroxidation was studied. Parenteral administration of argemone oil (5 ml/kg body weight) daily for 3 days produced a significant increase in both non-enzymatic and NADPH-supported enzymatic lipid peroxidation in whole homogenate, mitochondria, and microsomes. Lipid peroxidation aided by various pro-oxidants, namely Fe2+, Fe2+/ADP and ascorbic acid also revealed a significant enhancement in the whole homogenate, mitochondria and microsomes of argemone oil-treated rats. Further, when compared with whole homogenate, the hepatic mitochondria and microsomes of either control or argemone oil-treated rats showed a 4- and 6-fold increase in non-enzymatic, and a 5- and 18-fold increase in NADPH-dependent enzymatic lipid peroxidation, respectively. Similarly, both mitochondrial and microsomal fractions showed a 5- and 7-fold increase in Fe2+-, and a 12- and 15-fold increase in either Fe2+/ADP- or ascorbic acid-aided lipid peroxidation, respectively. These results suggest that the hepatic microsomal as well as the mitochondrial membrane is vulnerable to the peroxidative attack of argemone oil and may be instrumental in leading to the hepatotoxicity symptoms noted in argemone poisoning victims.

Mitochondrial function in rats is affected by modification of membrane phospholipids with dietary sardine oil.

Phospholipids of heart and liver of rats fed a diet containing sardine oil had more omega 3 polyunsaturated fatty acids and less omega 6 polyunsaturated fatty acids than those of rats fed corn oil, whereas there was little difference in the fatty acid composition of brain phospholipids. The mass of phospholipid classes in rat heart mitochondria was not changed, but their fatty acid compositions were altered. Modification of the fatty acid compositions of mitochondrial phosphatidylcholine and phosphatidylethanolamine reached a plateau after 10 d of feeding, but that of cardiolipin continued for 30 d. The O2 consumption rate of rat heart mitochondria decreased as the fatty acid composition of the phospholipids changed. This may be due to the reduction of the activity of cytochrome c oxidase, which requires cardiolipin for its activity. However, F1F0-ATPase, which also requires cardiolipin, was activated under the same conditions.

Oscillatory behaviour and unsaturated fatty acid composition of diabetic liver mitochondria.

Volume oscillations of liver mitochondria resulting from valinomycin induced K+ transport, may be represented by the equation At/Am = C'.exp(-beta t).sin(omega 1t+ psi) where At is the oscillation amplitude at time t; Am, the maximal amplitude; beta, the damping coefficient, omega 1 the oscillation frequency, and C' and psi, constants. The kinetic parameters beta and omega 1 increased as a function of valinomycin concentration. Measurement of beta and omega 1 for mitochondria from normal rats (A); diabetic rats (B), and normal rats fed corn oil or lard-supplemented diets (C and D, respectively), yielded an increase in beta (P less than 0.05) in B and D as compared with A, and a decrease in omega 1 in B and D as compared with A and C, respectively. Analysis of mitochondrial lipids revealed significant diminution of arachidonic acid and other polyenoic fatty acids in diabetic and lard-fed rats, as compared with normal rats and corn oil-fed rats, respectively. The conclusion is drawn that the abnormal oscillatory behaviour of diabetic liver mitochondria is related to the alteration of the membrane fatty acid composition.

X-ray microanalysis of calcium, potassium, and phosphorus in liver mitochondria stressed by carbon tetrachloride.

Previous measurements of elemental concentrations in liver mitochondria have generally required homogenization and fractionation of liver tissue, a procedure in which it is difficult to rule out ion movement between subcellular units. New techniques involving cryoultramicrotomy of rapidly frozen tissue, high resolution scanning transmission electron microscopy, and X-ray microanalysis were used to measure those elements in rat liver mitochondria reported to have changed following oral administration of carbon tetrachloride (CCl4). Increases in liver mitochondrial calcium were found 24 hr following intoxication by CCl4. Significant early (2 hr) mitochondrial increases in potassium and phosphorus were found following administration of CCl4. The electron microscope technique using quick-frozen samples promises to allow measurement of intracellular ionic concentrations under virtually lifelike conditions.

[Role of hyperthyroidism and the fatty component of the diet in changes in the fatty acid composition of the liver mitochondrial lipids in rats]. / Rol' gipertireoza i zhirovogo komponenta diety v modifikatsiiakh zhirno-kislotnogo sostava lipidov mitokhondrii pecheni krysy.

The influence of hyperthyrosis and the diet fat component on the hepatic mitochondrial fatty-acidic content was studied in Wistar rats. The animals, divided into two groups, were kept within 20 days on synthetic diets enriched with proteins (18%), carbohydrates (56%), fats (26%), vitamin and salt mixtures. The first group of animals was given the butter diet ("B" group) and the second one received the sunflower-seed oil ration ("S" group). It was found that after three weeks from the beginning of the diet the content of hepatic mitochondrial fatty acids was changed according to the fatty-acidic spectrum of alimentary fats. However, the fatty acid unsaturation indices, i.e. the unsaturated fatty acid % X unsaturated bond number, were not different in both mitochondrial populations studied. Hyperthyrosis (induced by 50 micrograms of thyroxin/100 g body weight within 5 successive days intraperitoneally), simulated in the presence of the above diets, not only intensified changes, caused by the diet in the mitochondrial fatty acid content, but induced further variance in the fatty-acidic spectra, being distinctly seen in the "B" group animals. In particular, hyperthyrosis in these animals was accompanied by a fall of linoleic (25%) and arachidonic (36%) acids in the mitochondrial lipid content, being the main cause of decreasing the mitochondrial lipid unsaturation indices by 26%. The alteration of lipid parameters in mitochondria of hyperthyroid animals of the "S" group was less pronounced, being 6%, 11% and 9%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence for selenocysteine in ovine tissue organelles.

Subcellular fractions were prepared by differential centrifugation from heart and liver of a lamb labeled with 75Se-selenite. Crude fractions of nuclei, mitochondria, and microsomes from both tissues were solubilized with sodium dodecyl sulfate and chromatographed on columns of sephacryl S-200. A low molecular weight (MW) 75Se labeled cardiac cytosol protein (approximately 10,000 daltons) was partially purified by gel filtration chromatography. The major 75Se peaks from the sephacryl columns and the low MW cardiac protein were hydrolyzed in HCl under an inert atmosphere. When chromatographed on an amino acid analysis column, 75Se from each hydrolysate chromatographed in the identical position of 2,7-diamino-4-thia-5-selenaoctanedioic acid, the mixed oxidized dimer of cysteine and selenocysteine. The low MW cardiac protein was reacted with chloroacetate after reduction with borohydride. 75Se from a hydrolysate of this derivatized protein eluted in the same position as Se-carboxymethylselenocysteine on the amino acid analysis column. Thus, selenocysteine appears to be the predominant form of selenium in ovine heart and liver.

On the occurence and composition of dense particles in mitochondria in ultrathin frozen dry sections.

Clusters of dense particles were observed irregularly in mitochondrial profiles of shock-frozen brown adipose tissue and liver when cryosectioned at a chamber temperature of -80 degrees C and not if sectioning was performed at -110 degrees C. The particles are rich in Ca and P (Ca/P =0.5); they are therefore not any form of tricalcium orthophosphate (e.g. hydroxyapatite). They apparently form by electrolyte diffusion in the section and therefore cannot be considered as representing the in vivo pool of mitochondrial calcium.

Highly polar non-glycerol containing lipids present in our mitochondrial membranes.

Aqueous 80% ethanol extracts from the outer mitochondrial membranes contained a series of compounds, insoluble in chloroform-methanol (2:1) and soluble in chloroform-methanol-water (10:10:3). These compounds contain fatty acids, amino acids and hexoses. Procedures are described for the extraction, purification and cromatographic separation of these compounds. Five of them have been partially characterised. Some structural data are given. It is suggested that some relationship could exist with the glycosylation of the outer membrane proteins.

[Concentration and subcellular distribution of iron and copper in the pig liver. II. Studies on the livers of porkers and swine for slaughter with regard to the addition of copper sulfate to the diet]. / Konzentration und subzelluläre Verteilung von Eisen und Kupfer in der Leber von Schweinen. II. Untersuchungen an der Leber von Läufer- und Schlachtschweinen unter besonderer Berücksichtigung eines Zusatzes von Kupfersulfat zur Futterration

In the livers of weaners, an average concentration of storage iron of 69.1 +/- 47.6 mug, and in those of pigs for slaughter, 326 +/- 54 mug/g tissue was measured. Addition of 250 ppm of copper as CuSO4-5H2O to the animals' food led to a significantly lower concentration of 248 +/- 63-5 mg Fe/g liver in pigs for slaughter. Of the storage iron, 66-1% for weaners, 79.2% for pigs for slaughter, and 76% for animals given Cu-supplemented food were localized in the microsomal fraction and in the cytosol. The copper concentration in the liver was 5.2 +/- 0.6 mug/g in weaners, 8.1 +/- 2.4 mug/g in pigs for slaughter and 120 +/- 83 mug/g in animals kept on a Cu-supplemented diet, Of these, 72.6% (pigs for slaughter) and 71.9% (weaners) came to the microsomal fraction and the cytosol, whereas addition of 250 ppm copper to the food ration enhanced the proportion in the nuclear fraction from 7.7 to 29.5%, and in the mitochondrial fraction, from 19.8 to 45.1%. The percent distribution of the copper on the subcellular fractions depends on the copper concentration in the liver: in the range of 5-12 mug/g tissue, increased copper concentration in the liver caused preferential localization of the copper in the cytosol, whereas between 25 and 330 mug/g tissue the copper was stored subcellularly in the following order: mitochondrial, nuclear, cytoplasmatic and microsomal fractions.