scholarly journals The nature of the acid-volatile selenium in the liver of the male rat

1973 ◽  
Vol 134 (1) ◽  
pp. 283-293 ◽  
Author(s):  
A. T. Diplock ◽  
Christine P. J. Caygill ◽  
Elizabeth H. Jeffery ◽  
C. Thomas
Keyword(s):  
Vitamin E ◽  
Rat Liver ◽  
Microsomal Fraction ◽  
Current Knowledge ◽  
Liver Homogenate ◽  
Selenium Deficiency ◽  
Male Rat ◽  
Anaerobic Conditions ◽  
Volatile Material ◽  
Acid Labile

1. The properties of rat liver acid-volatile selenium have been compared with those of H2Se and (CH3)2Se. 2. In model experiments oxidation-sensitive H275Se was trapped quantitatively under anaerobic conditions in 0.1m-AgNO3, and (CH3)275Se was trapped quantitatively in 8m-HNO3. The acid-labile selenium of a liver homogenate, and of a microsomal fraction, was found to behave quite unlike (CH3)275Se and in a manner indistinguishable from H275Se. 3. It was concluded that the acid-volatile material is certainly not (CH3)2Se and that it is probably H2Se. 4. The significance of these findings is discussed in relation to current knowledge about the metabolism and detoxication of selenium, and a scheme is proposed which incorporates this knowledge with recent observations on the interactions between trace amounts of selenium and tocopherol, and the production of acute selenium deficiency by Ag+ in vitamin E-deficient rats.

Chromogenic Assays for the Determination of Prothrombin Related Material in Rat Liver Fractions.

1979 ◽  
Author(s):  
Linda J Beecroft
Keyword(s):  
Rat Liver ◽  
Vitamin K ◽  
Microsomal Fraction ◽  
Liver Homogenate ◽  
Chromogenic Substrates ◽  
Related Material ◽  
Esterolytic Activity ◽  
Echis Carinatus ◽  
Microsomal Pellet

Clotting assays are not easily applied to turbid solutions such as microsomal fractions. With the development of chromogenic substrates, the esterolytic activity of prothrombin related material can be assayed biochemically in such systems. Liver fractions were prepared by differential centrifugaron. Liver homogenate was centrifuged at 10,000 g. for 10 minutes to yield supernatant 1.Supernatant 1 was further centrifuged at 105,000 g for 60 minutes to yield the microsomal pellet and supernatant 2. Taipan and Echis carinatus snake vanoms were used to generate esterolytic activity in the various liver fractions. In all fractions the esterolytic activity generated by E. carinatus venom was greater than that generated by Taipan Venom. Both assays indicated that the microsomal pellet had similar esterolytic activity to supernatant 2. When liver fractions were prepared from warfarin treated rats, the assays revealed that the relative proportions of prothrombin related material in the fractions had altered. The esterolytic activity of the microsomal fraction was found to be greatly increased whilst supernatant 2 had no detectable activity.Warfarin treated rats have greatly decreased levels of prothrombin in the plasma due to inhibition of vitamin K-dependent carboxylation in the liver. It is suggested that the lack of prothrombin in the plasma reflects the lack of soluble prothrombin in supernatant 2, and the concomitant build-up of precursor forms bound to the microsomes.

scholarly journals The dependence on vitamin E and selenium of drug demethylation in rat liver microsomal fractions

1975 ◽  
Vol 146 (2) ◽  
pp. 339-350 ◽  
Author(s):  
A S M Giasuddin ◽  
C P J Caygill ◽  
A T Diplock ◽  
E H Jeffery
Keyword(s):  
Enzyme Activity ◽  
Vitamin E ◽  
Rat Liver ◽  
Selenium Deficiency ◽  
Wide Range ◽  
Km Value ◽  
Demethylase Activity ◽  
In Vitro Induction ◽  
Substrate Concentrations

1. The effects of vitamin E deficiency, and of vitamin E and selenium deficiency, on rat liver microsomal aminopyrine demethylase activity were investigated. It was found that, over a wide range of substrate concentrations, the enzyme activity in preparations from deficient animals was significantly lower than that in controls. 2. Addition of antioxidants in vitro, either to the homogenization or to the assay media, was without significant effect on the depressed enzyme activity. Castration and alteration in dietary protein concentration were also without effect. The rate of oxidation of NADPH was however, lower in preparations from deficient animals. 3. Lineweaver-Burk plots of the reciprocal of enzyme activity and substrate concentration showed a higher Km value in preparations from vitamin E-deficient animals, irrespective of whether selenium was present; the Vmax. was unaffected. These parameters were unchanged when antioxidants were added in vitro. Induction with phenobarbitone and 3-methylcholanthrene showed large changes in Km value which, for preparations from vitamin E-deficient animals, was higher than that for corresponding controls. 4. Examination of the synergism between NADH and NADPH as donors of reducing equivalents for aminopyrine demethylation showed that vitamin E and selenium were only minimally involved in the phenomenon. However, both the initial rate and the extent of demethylation were significantly lower in vitamin E- and selenium-deficient preparations and both nutrients were required for the restoration of full activity. 5. The significance of these results is discussed in the light of our working hypothesis.

scholarly journals ISOLATION OF SMOOTH VESICLES AND FREE RIBOSOMES FROM RAT LIVER MICROSOMES

1962 ◽  
Vol 12 (1) ◽  
pp. 17-29 ◽  
Author(s):  
J. Chauveau ◽  
Y. Moulé ◽  
C. Rouiller ◽  
J. Schneebeli
Keyword(s):  
Cytochrome C ◽  
Rat Liver ◽  
Microsomal Fraction ◽  
Sucrose Solution ◽  
Liver Microsomes ◽  
Liver Homogenate ◽  
Enzymatic Activities ◽  
Rat Liver Microsomes ◽  
Differential Centrifugation ◽  
Cytochrome C Reductase

Microsomes, isolated from rat liver homogenate in 0.88 M sucrose, have been fractionated by differential centrifugation. The 2nd microsomal fraction, sedimented between 60 minutes at 105,000 g and 3 hours at 145,000 g, consists mainly of smooth vesicles, free ribosomes, and ferritin. By utilizing the differences in density existing between the membranes and the granular elements it has been possible to separate the smooth membranes from the free ribosomes and ferritin. The procedure is to resuspend the 2nd microsomal fraction in a sucrose solution of 1.21 or 1.25 density and centrifuge it at 145,000 g for 20 or 40 hours. A centripetal migration of membranes and a centrifugal sedimentation of granular elements are obtained. Phospholipids, as well as the enzymatic activities DPNH-cytochrome c reductase, glucose-6-phosphatase and esterase are localized in the membranes. The free ribosomes have been purified by washing. A concentration of 200 µg RNA per mg nitrogen has been reached. RNA is also present in the membranes. These results are discussed in relation to current views on microsomal structure and chemistry.

scholarly journals Metabolism of a glutathione conjugate of 2-hydroxyoestradiol by rat liver and kidney preparations in vitro

1970 ◽  
Vol 116 (5) ◽  
pp. 913-917 ◽  
Author(s):  
John S. Elce
Keyword(s):  
Rat Liver ◽  
Microsomal Fraction ◽  
Male Rat ◽  
Amino Group ◽  
Glutathione Conjugate ◽  
Acetyl Coenzyme A ◽  
Adult Male Rat ◽  
Liver And Kidney

Adult male rat liver and kidney preparations were incubated with (2-hydroxyoestradiol-1-yl)[35S]glutathione. The glutamic acid and glycine residues were removed by enzymes present in the kidney microsomal fraction; the liver preparations had no effect. The resulting 2-hydroxyoestradiol–cysteine conjugate was acetylated at the α-amino group by both liver and kidney homogenates fortified with acetyl-coenzyme A, but not significantly in the absence of this coenzyme, or by liver or kidney slices. These results suggest that an oestrogen–glutathione conjugate, if formed in vivo, would be converted into the corresponding mercapturic acid before excretion.

scholarly journals A Biochemical and Morphological Study of Rat Liver Microsomes

1960 ◽  
Vol 7 (3) ◽  
pp. 547-557 ◽  
Author(s):  
Y. Moulé ◽  
C. Rouiller ◽  
J. Chauveau
Keyword(s):  
Rat Liver ◽  
Microsomal Fraction ◽  
Sucrose Solution ◽  
Liver Microsomes ◽  
Liver Homogenate ◽  
Sodium Deoxycholate ◽  
Point Of View ◽  
Rat Liver Microsomes ◽  
Experimental Conditions ◽  
Microsome Fraction

Microsomes isolated by differential centrifugation from a rat liver homogenate in 0.88 M sucrose solution have been studied from the biochemical and morphological point of view. 1. Under these experimental conditions, the "total microsome" fraction was obtained by centrifuging the cytoplasmic extract free of nuclei and mitochondria, for 3 hours at 145,000 g. Morphologically, the total microsomes consist mainly of "rough-surfaced membranes" and "smooth" ones. 2. The total microsomes have been divided into 2 subfractions so that the 1st microsomal fraction contains the "rough" vesicles (2 hours centrifugation at 40,000 g) while the 2nd microsomal fraction consists essentially of smooth vesicles, free particles, and ferritin (centrifugation of the supernatant at 145,000 g for 3 hours). 3. By the action of 0.4 per cent sodium deoxycholate in 0.88 M sucrose, it was possible to obtain a pellet for each of the 2 fractions which consisted of dense particles, rich in RNA, poor in lipids, and which represented about 50 to 60 percent of the RNA and 10 to 15 per cent of the proteins. The results have been discussed taking into consideration the hypothesis of the presence of RNA in the membranes of microsomal vesicles.

scholarly journals 4,4′-dimethylcholesta-7,9,14-trienol is an intermediate in the demethylation of dihydroagnosterol

1977 ◽  
Vol 166 (1) ◽  
pp. 17-20 ◽  
Author(s):  
I A F Tavares ◽  
K A Munday ◽  
D C Wilton
Keyword(s):  
Rat Liver ◽  
Liver Homogenate ◽  
Anaerobic Conditions ◽  
Microsomal Preparation ◽  
Aerobic Conditions ◽  
Liver Microsomal Preparation

1. 4,4′-Dimethylcholesta-7,9,14-trienol is an intermediate in the metabolism of dihydroagnosterol to cholesterol by rat liver homogenate. 2. This triene is reduced by a rat liver microsomal preparation in the presence of NADPH to give 4,4′-dimethylcholesta-7,9-dienol under anaerobic conditions. 3. Reduction of the triene in the presence of [4-3H2]NADPH resulted in the incorporation of 3H into the product. 4. Under aerobic conditions the triene is converted into cholesterol by a rat liver homogenate.

THE EFFECT OF VITAMIN E ON THE BIOCHEMICAL PARAMETERS IN THE EXPERIMENT

2020 ◽  
Vol 93 (1) ◽  
pp. 103-105
Author(s):  
I. Shukurov ◽  
◽  
Ch. Khayrullayev ◽  
M. Gulomova ◽  
F. Umurov
Keyword(s):  
Acute Pancreatitis ◽  
Cytochrome P450 ◽  
Vitamin E ◽  
Rat Liver ◽  
Biochemical Parameters ◽  
Microsomal Fraction ◽  
Monooxygenase System ◽  
Experimental Acute Pancreatitis ◽  
Liver Cytochrome ◽  
Cytochrome P 450

The effect of vitamin E on rat liver cytochrome P-450 in experimental acute pancreatitis (AP) was studied. The animals were divided into 4 groups. The obtained data were compared with the indicators of the 1–st group (intact). During the experiment, the development of AP showed a decrease in the content of cytochrome P450 in the microsomal fraction. The administration of vitamin E to animals of the 4th group led to an increase in the content of cytochrome P-450, strengthening the protection of the liver, the abolition of inhibition of the monooxygenase system of the liver.

Influence of Testosterone Propionate on the Succinic Dehydrogenase Activity of Male Rat Liver

1958 ◽  
Vol 193 (1) ◽  
pp. 73-74 ◽  
Author(s):  
T. H. Rindani
Keyword(s):  
Dehydrogenase Activity ◽  
Rat Liver ◽  
Succinic Dehydrogenase ◽  
Liver Homogenate ◽  
Male Rats ◽  
Male Rat ◽  
Succinic Dehydrogenase Activity ◽  
Hormone Administration ◽  
Wet Weight ◽  
Testosterone Administration

Castration of male rats was shown previously to cause an increase of the succinic dehydrogenase activity in male rat liver homogenate. The present study was undertaken to examine if this increase was influenced by testosterone administration to the castrated animals over different periods of duration. It was observed that testosterone treatment counteracted the increase in the enzyme activity caused by castration and that this effect was more marked with longer duration of the hormone administration. Further the succinic dehydrogenase activity was not related directly to the wet weight of the liver.

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