Release of synthesized lipids by isolated Wistar rat liver perfused by labelled oleic acid and glycerol]

After perfusions with oleic acid (9, 10-3H) and glycerol (1-14C) of isolated livers from wistar Rats, previously subjected to fasting, the study of the TG and PL synthesized by the liver and released in the circulation gives of evidence similar ways of metabolising TG and PL. Two liver pools are present: -- a storage pool, built with slow exchanges of AG of endogenous glycerolipids. In our experiments, the TG: 16 : 0 18 : 1 18: 2 and 16 : 0 18 : 1 18 : 1 and the PL: PE and PC are the glycerolipids of liver constitution: -- a pool of liver secretion. TG and PL are formed according to a rapid de novo synthesis using preferentially the exogenous substrates. They are released in the circulation. In our experiments, the TG secreted are the TG 18 : 1 18 : 1 18 : 1 and 16 : 0 18 : 1 18 : 2, the PL are the PE, AP and LPC.     

Comparison in genetically obese and normal rats in the secretion of lipids synthesized from labeled lauric and oleic acids and glycerol in isolated perfused liver]

(1) Isolated livers of previously fasted fafa and Wistar Rats are perfused with labelled oleic acid and glycerol. Two pools of synthesized lipids are studied: --a pool of liver lipids: labelled TG 16:0, 16:0, 18:1, 16:0, 18:1, 18:1 and 18:1, 18:1, 18:1 are synthesized more by the fafa than by the Wistar Rat liver, The TG 16:0, 18:1, 18:2 appears in the liver of the 2 rat strains. After a 30 min. perfusion, the PL are synthesized less by the fafa than by Wistar Rat liver; --a pool of lipids released in the circulation. The labelled tG 16:0, 18:1, 18:2, are increased in the perfusate of fafa rat. The labelled TG 18:1, 18:1, 18:2 and 18:1, 18:2, 18:2 are in the same amount. (2) The liver synthesis of TG 12:0, 12:0, 12:0 is demonstrated in the fafa Rat by a lauric acid perfusion. This TG is not present in circulation, when a Wistar Rat liver synthesizes and releases with this TG, TG containing 1 or 2 molecules of lauric acid.     

Rapid recording of the fluorescence spectrum emitted by an isolated living cell]

In order to use the selectivity of fluorescence emission for biomedical purposes, a microspectrofluorimeter has been built around an inverted microscope. The excitation is supplied by a 450 W Xenon lamp coupled with a monochromator allowing excitation from 230 to 600 nm. The fluorescence is analysed by a Grism (association prism-grating) and the spectrum focused on the 500 channels of the target of an Optical Multichannel Analyser. Related to good resolution and dispersion (0.44 nm/channel), improvement of signal to noise ratio (dark current suppression, and accumulation of spectra), this microspectrofluorimeter with high sensitivity is well adapted to the study of biological mechanism in single living cells (macrophages, monocytes, lumphocytes).     

Uptake and incorporation of labeled oleic acid and glycerol by the isolated and perfused liver of the Wistar rat]

After perfusion by oleic acid (9-10(-3)H) and glycerol (1(-14)C) previously starved Wistar rats, the synthesis of hepatic TG and PL follows the two following different method: -- during the first minutes of perfusions, the most important method synthesis of TG and especially of PL is a de novo synthesis utilizing glycerol and the exogenous AG. The TG synthesized are 18:1 18:1 18:1 and 16:0 18:1 18:2 the PL synthesized are LP, AP and LPC; -- during perfusions of long duration (30, 60, 120 min.), the major method of synthesis of TG and PL is an active exchange of AG of the endogenous glycerolipids. The TG synthesized are 16:0 18:1 18:1 and 16:0 18:1 18:2 the PL synthesized are PE and PC.     

The effects of 4 detergents on the respiration of mitochondria isolated from rat liver]

The effects of these four detergents (two non-ionic: Titron X100 and Tween 80, two ionic: sodium cholate and sodium dedeoxycholate) upon the respiratory intensities of mitochondria and upon the ADP/0 and respiratory control ratios were observed. At low concentrations and in the absence of exogenous ADP, non ionic as well as ionic detergents provoked a threefold (or fourfold) increase of the respiratory intensities of mitochondria. At higher concentrations, the four detergents were inhibitory for mitochondrial oxidations in the order: Triton X 100 greater than DOC greater than cholate greater than Tween 80. At increasing doses, the four detergents progressively decreased the phosphorylating capacities of mitochondria.     

Depression by ethionine of phosphorylating oxidation in hepatic mitochondria

Summary Induction of hepatic steatosis and suppression of hepatic ATP levels, protein synthesis and gluconeogenesis subsequent to administration of ethionine may be consequences of interference by this compound with mitochondrial phosphorylation of ADP. The mitochondrial dysfunction is not a direct action of ethionine on the organelle.     

Depression by ethionine of phosphorylating oxidation in hepatic mitochondria

Induction of hepatic steatosis and suppression of hepatic ATP levels, protein synthesis and gluconeogenesis subsequent to administration of ethionine may be consequences of interference by this compound with mitochondrial phosphorylation of ADP. The mitochondrial dysfunction is not a direct action of ethionine on the organelle.     

Lack of amino acid incorporation by isolated mitochondria from respiratory-deficient cytoplasmic yeast mutants

Zusammenfassung Die Mutation der mitochondrialen DNA, die in den atmungsdefekten Hefen resultiert, führt zu dem Verlust der Fähigkeit der isolierten Mutantenmitochondrien,¹⁴C-Leuzin in die TES-unlösbare Fraktion zu inkorporieren.     

Some properties of external NADH oxidation by human placental mitochondria

Summary Isolated human term placenta mitochondria catalyse oxidation of external NADH in the presence of cytochrome c. This reaction is insensitive to the respiratory chain inhibitors such as rotenone and antimycin A, and is not coupled to phosphorylation. Comparison of the effect of Mg⁺⁺ ion on NADH plus cytochrome c oxidation by human term placental, human skeletal muscle and rat skeletal mitochondria showed that Mg⁺⁺ ion exerts an inhibitory effect in the case of human mitochondria and a stimulatory effect in the case of rat skeletal muscle mitochondria.This work has been supported by a grant from Ministry of Higher Education Science and Technology within the project No. 01.02.     

Preparation of isolated cells from rat heart

Summary Suspensions of isolated cells from rat heart were prepared and the data for viability and yield are given. Glucose uptake by the cells was mediated by a carrier system.The technical assistance of Mr.E. T. Potter, Mr.K. D. Patel and Mr.M. Griffin is gratefully acknowledged.     

Some properties of external NADH oxidation by human placental mitochondria.

Isolated human term placenta mitochondria catalyse oxidation of external NADH in the presence of cytochrome c. This reaction is insensitive to the respiratory chain inhibitors such as rotenone and antimycin A, and is not coupled to phosphorylation. Comparison of the effect of Mg++ ion on NADH plus cytochrome c oxidation by human term placental, human skeletal muscle and rat skeletal mitochondria showed that Mg++ ion exerts an inhibitory effect in the case of human mitochondria and a stimulatory effect in the case of rat skeletal muscle mitochondria.     

Measurement of fluorescence decay of substances absorbed by an isolated living cell: an experimental device and early results]

A microfluorometric system allowing the mesurements of fluorescence decay (i.e. fluorescence lifetime) has been built. It will complete the microspectrofluorometric studies of absorbed compounds-polycyclic aromatic hydrocarbons, metabolites of benzo (a) pyrene-by single living cells and allows a better understanding of the intake and metabolisation of these compounds. The preliminary results with benzo (a) pyrene, dibenzocarbazole, pyrene are shown.     

Effect of hypoxia on glycolysis in isolated fetal rat heart]

Glycolysis was assessed in the isolated foetal Rat in hypoxia. Measurements were made of glucose uptake, lactate output, C14 glucose incorporation into glycogen and tissular levels of ATP, PCr, glycogen and lactate. Glycolysis was stimulated by hypoxia to a greater extent in the young foetal heart of 16.5 days post coitum than in the foetal heart at term. Thus high energy phosphates were maintained at a higher level in the younger heart. The results are discussed in relation to the high resistance to hypoxia of the foetal heart.     

Structure-activity relationship of various ephedrine isomers on noradrenaline uptake by the isolated perfused rabbit heart]

(-)Ephedrine, (+) Ephedrine, (-) psi ephedrine and (+) psi ephedrine inhibit both the neuronal and extraneuronal uptakes of noradrenaline in isolated Rabbit heart. (-) ephedrine is the most active isomer for the inhibition of both neuronal and extraneuronal uptakes. The relative inhibition potential of the three other isomers is not the same when applied to one or other uptake.     

Comparison in genetically obese and normal rats of the uptake and incorporation of labelled lauric acid, oleic acid, and glycerol by the isolated perfused liver]

Lauric acid, labelled oleic acid and glycerol are perfused in isolated liver of fafa Rats and Wistar Rats previously subjected to fasting. They synthesize TG and PL de novo, though in long time experiments with the normal Rat, the most important method of synthesis is an exchange of AG of the endogenous glycerolipids. However PL are not synthesized with lauric acid. In the livers of fafa Rats the synthesis of TG with oleic acid and glycerol is higher than in livers of Wistar Rats: 16:0 18 : 1 18: 1, 16:0 18: 1 18: 2, 18 : 1 18 :1 18:1, 16 : 0 16 :0 18 : 1 (this TG is not present in liver of Wistar Rat). The hepatic synthesis of PL by the fafa Rat, is less important after 15 min while it is important with Wistar Rats. The synthesized TG with lauric acid (only the TG 12 : 0 12 : 0 12 : 0 with the fafa Rat) are more rapidly oxidized by liver of obese Rat than by liver of normal Rat.     

Incorporation of3H-UTP into mitochondria isolated from cytoplasmic and nuclear respiratory-deficient yeast mutants

Zusammenfassung Aus verschiedenen cytoplasmatischen ^–) und nuklearen (p) atmungsdefekten Hefemutanten isolierte Mitochondrien weisen eine Aktino-mycin-empfindliche Inkorporation von³H-UTP in die TCS-unlösliche Fraktion auf. Die Absenz der mitochondrialen Proteosynthese dieser Mutanten könnte daher auf einen Hemmer im Translationsmechanismus zurückgeführt werden.