scholarly journals The metabolism of dipotassium 2-hydroxy-5-nitrophenyl [35S]sulphate, a substrate for lysosomal arylsulphatases A and B

1967 ◽  
Vol 105 (3) ◽  
pp. 1003-1012 ◽  
Author(s):  
T. G. Flynn ◽  
K S Dodgson ◽  
G M Powell ◽  
F A Rose
Keyword(s):  
Bile Duct ◽  
Kidney Function ◽  
Intraperitoneal Injection ◽  
Chromogenic Substrate ◽  
Metabolic Fate ◽  
Isolated Rat Liver ◽  
Anaesthetized Rats ◽  
Free Ranging ◽  
Rat Livers ◽  
Isolated Rat

The metabolic fate of dipotassium 2-hydroxy-5-nitrophenyl [35S]sulphate ([35S]NCS), a chromogenic substrate for lysosomal arylsulphatases A and B, has been studied in rats. Intraperitoneal injection of [35S]NCS into free-ranging animals is followed by excretion of the bulk of the radioactivity in the urine within 24hr., less than 13% being eliminated as inorganic [35S]sulphate. Most of the urinary radioactivity can be accounted for as [35S]NCS, but small amounts of a labelled metabolite are also present. Experiments in which [35S]NCS was injected intravenously into anaesthetized rats with bile-duct and bladder cannulae confirm that the ester is rapidly excreted in the urine. However, small amounts of radioactivity appear in bile, mainly in the form of the metabolite detected in urine. When [35S]NCS is perfused through the isolated rat liver, about 35% of the dose is hydrolysed within 3hr. Similar results are obtained if [35S]NCS is injected into anaesthetized rats in which kidney function has been eliminated by ligature of the renal pedicles. The labelled metabolite has been isolated from bile obtained by perfusing several rat livers with blood containing a total of 100mg. of [35S]NCS. It has been identified as 2-β-glucuronosido-5-nitrophenyl [35S]sulphate. The implications of the various findings are discussed. The Appendix describes the preparation of [35S]NCS.

scholarly journals The Metabolic Fate of Pentylenetetrazol in the Rat

1971 ◽  
Vol 49 (4) ◽  
pp. 356-365 ◽  
Author(s):  
G. K. W. Ko ◽  
E. A. Hosein
Keyword(s):  
Elemental Analysis ◽  
Intraperitoneal Injection ◽  
Mobile Phase ◽  
Phase Distribution ◽  
Liver Perfusion ◽  
Metabolic Fate ◽  
Isolated Rat Liver ◽  
Water Saturated ◽  
Sulfur Containing ◽  
Isolated Rat

Pentylenetetrazol administered to rats was metabolized to a derivative which was excreted in the urine along with unchanged pentylenetetrazol. Pentylenetetrazol and its metabolite can be separated on paper chromatograms developed in water-saturated isobutanol. The substances, however, are chromatographically inseparable with water as the mobile phase. Distribution of tritium-labelled pentylenetetrazol in the rat after intraperitoneal injection indicated that it was readily taken up by the liver. Perfusion of the isolated rat liver with citrated blood containing tritiated pentylenetetrazol demonstrated that the metabolite was formed in the intact liver. Formation of the metabolite was inhibited by SKF 525A. The metabolite was isolated from the urine of rats treated with pentylenetetrazol on an Amberlite XAD-2 column and elemental analysis showed it to be a sulfur-containing derivative.

Ultrastructural changes in isolated rat liver perfused with cyclic heptapeptide toxins from norwegian freshwater cyanobacteria (blue-green algae)

1987 ◽  
Vol 45 ◽  
pp. 858-859
Author(s):  
A.S. Dabholkar ◽  
W.W. Carmichael ◽  
K. Berg ◽  
J. Wyman
Keyword(s):  
Ultrastructural Changes ◽  
Sprague Dawley ◽  
Isolated Rat Liver ◽  
Blue Green Algae ◽  
Sprague Dawley Rats ◽  
Cyclic Heptapeptide ◽  
Intracellular Changes ◽  
Oscillatoria Agardhii ◽  
Rat Livers ◽  
Isolated Rat

Intracellular changes in the hepatocytes of isolated rat livers perfused with cyclic heptapeptide toxins are described. The toxins used are 1) -Ala-Leu- β-methyl isoAsp-Arg-ADDA-isoGlu-mdha (M.W. 944) from Microcystis aeruginosa- Lake Akersvatn, Norway; 2) -Ala-Arg-isoAsp-Arg-ADDA-isoGlu-mdha (M.W. 1023) from Oscillatoria agardhii var. - Lake Kolbatnvatn, Norway; 3) -Ala-Arg-isoAsp-Arg-ADDA-isoGlu-dha (M.W. 1009) from Oscillatoria agardhii var. isothrix - Lake Froylandsvatn, Norway. Approximate LD intraperitoneal mouse for the toxins is 50, 500 and 1000 μg/kg respectively.Livers were removed from male Sprague Dawley rats and perfused for 15 min with a blood-free perfusate (50 ml) followed by 60 min with perfusate containing i) 25, 50, or 200 μg of M. aeruginosa toxin ii) 50, 250, 500 or 1000 μg of O. agardhii var. toxin and iii) 1000, 2000, 2500 or 5000 μg of O. agardhii var. isothrix toxin. Control livers were perfused for 75 min with the blood-free perfusate.

scholarly journals The metabolism of potassium dodecyl [35S]-sulphate in the rat

1969 ◽  
Vol 111 (1) ◽  
pp. 43-51 ◽  
Author(s):  
W. H. B. Denner ◽  
A H Olavesen ◽  
Gillian M. Powell ◽  
K S Dodgson
Keyword(s):  
Butyric Acid ◽  
Liver Perfusion ◽  
Paper Electrophoresis ◽  
Whole Body ◽  
Hydroxybutyric Acid ◽  
Metabolic Fate ◽  
Anaesthetized Rats ◽  
Dilution Experiments ◽  
Free Ranging ◽  
Isolated Liver

The metabolic fate of potassium dodecyl [35S]sulphate was studied in rats. Intraperitoneal and oral administration of the ester into free-ranging animals were followed by the excretion of the bulk of the radioactivity in the urine within 12hr., approximately 17% being eliminated as inorganic [35S]sulphate. Similar results were obtained in experiments in which potassium dodecyl [35S]sulphate was injected intravenously into anaesthetized rats with bile-duct and ureter cannulae. Analysis of urinary radioactivity revealed the presence of a new ester sulphate (metabolite A). This metabolite was isolated, purified and subsequently identified as the sulphate ester of 4-hydroxybutyric acid by paper, thin-layer and gas chromatography, by paper electrophoresis and by comparison of its properties with those of authentic butyric acid 4-sulphate. The identity of the metabolite was confirmed by isotope-dilution experiments. When either purified metabolite A or authentic potassium butyric acid 4[35S]-sulphate was administered to free-ranging rats the bulk of the radioactivity was eliminated unchanged in the urine within 12hr., approx. 20% of the dose appearing as inorganic [35S]sulphate. Whole-body radioautography and isolated-liver-perfusion experiments implicated the liver as the major site of metabolism of potassium dodecyl [35S]sulphate. It is suggested that butyric acid 4-sulphate probably arises by ω-oxidation of dodecyl sulphate to a fatty acid-like compound, which is then degraded by β-oxidation.

scholarly journals Studies on the metabolism of oestrone sulphate. Comparative perfusions of oestrone and oestrone sulphate through isolated rat livers

1977 ◽  
Vol 166 (3) ◽  
pp. 363-371 ◽  
Author(s):  
Michael Höller ◽  
Wilhelm Grochtmann ◽  
Mechthild Napp ◽  
Heinz Breuer
Keyword(s):  
Liver Cell ◽  
Liver Tissue ◽  
Glucuronic Acid ◽  
First Passage ◽  
Large Reservoir ◽  
Isolated Rat Liver ◽  
Oestrone Sulphate ◽  
Rat Livers ◽  
Hydroxy Steroid ◽  
Isolated Rat

The metabolism of [4-14C]oestrone and of [6,7-3H2]oestrone sulphate was studied during cyclic perfusion and once-through perfusion of the isolated rat liver. The following results were obtained. 1. As shown by once-through perfusion, the two steroids are metabolized differently during the first passage through the organ. [4-14C]Oestrone was taken up by the liver and partly delivered as oestradiol-17β and oestriol into the medium. After uptake of [6,7-3H2]oestrone sulphate, only oestrone, liberated by hydrolysis, was delivered into the medium; no oestradiol-17β or oestriol could be detected in the medium after one passage through the organ. This indicates that intracellular oestrone, which was taken up as such, and oestrone, which derived from intracellular hydrolysis, may be metabolized in different compartments of the liver cell. 2. The results of the cyclic perfusion showed that intracellular oestrone is preferentially conjugated with glucuronic acid, and subsequently excreted into the bile. Intracellular oestrone sulphate is preferably reduced to oestradiol sulphate, thus indicating that oestrone sulphate is a better substrate for the 17β-hydroxy steroid oxidoreductase than is oestrone. 3. Albumin-bound oestrone sulphate acts as a large reservoir, and in contrast with free oestrone is protected from enzyme attack by its strong binding to albumin. 4. Oestrone sulphate is partly converted into the hormonally active oestrone by liver tissue. This suggests that liver not only inactivates oestrogens, but also provides the organism with oestrone, which is subsequently readily taken up by other organs.

Effect of UDCA on intracellular and biliary pH in isolated rat hepatocyte couplets and perfused livers

1991 ◽  
Vol 260 (1) ◽  
pp. G58-G69 ◽  
Author(s):  
M. Strazzabosco ◽  
S. Sakisaka ◽  
T. Hayakawa ◽  
J. L. Boyer
Keyword(s):  
Bile Duct ◽  
Ursodeoxycholic Acid ◽  
Intracellular Ph ◽  
Rat Hepatocyte ◽  
Biliary Epithelium ◽  
Acid Load ◽  
Rat Livers ◽  
Isolated Rat

To study how ursodeoxycholic acid (UDCA) increases biliary HCO3- concentration and alkalinizes bile, intracellular pH (pHi) and canalicular pH (pHc) were measured microfluorimetrically in isolated rat hepatocyte couplets (IRHC). Isolated perfused rat livers (IPRL) were also used to assess the roles of Cl-, HCO3-, and zone III hepatocytes. In IRHC, UDCA diminished pHi only when HCO3- was omitted. pHi recovery was inhibited by amiloride. UDCA did not affect pHi recovery from an acid load (NH4Cl) nor modify pHc (+HCO3-). In IPRL, biliary HCO3- concentration increased following UDCA despite removal of Cl- (to inhibit Cl(-)-HCO3- exchanger) or destruction of zone III hepatocytes with digitonin. Moreover, when HCO3- was omitted from the perfusate, biliary pH rose following UDCA even though the hypercholeresis was abolished. Thus 1) hepatic UDCA uptake represents an acid load that is counteracted by Na(+)-H+ exchange when HCO3- is absent; 2) UDCA does not alkalinize pHc; and 3) alkalinization of biliary pH in IPRL is not HCO3- dependent, does not involve Cl(-)-HCO3- exchange, or zonal differences in UDCA metabolism or excretion. UDCA appears to alkalinize bile by protonation within the bile duct lumen. UDCAH may then cross the biliary epithelium.

Simultaneous perfusion of [4-14C]oestriol and [6,9-3H2]oestriol 16α-monoglucuronide through the isolated rat liver

1982 ◽  
Vol 100 (1) ◽  
pp. 57-62 ◽  
Author(s):  
M. Höller ◽  
H. Weber ◽  
H. Breuer
Keyword(s):  
Rat Liver ◽  
Glucuronic Acid ◽  
Small Extent ◽  
Isolated Rat Liver ◽  
Metabolic Reactions ◽  
Biliary Metabolite ◽  
Rat Livers ◽  
Isolated Rat

Abstract. Equimolar concentrations of [4-14C]oestriol and [6,9-3H2]oestriol 16α-monoglucuronide were simultaneously perfused through isolated rat livers. Oestriol was hydroxylated to 2-hydroxyoestriol and 6ξ-hydroxyoestriol; 2-hydroxyoestriol was further methylated to 2-methoxyoestriol. Oxidoreduction of oestriol led to the formation of 16α-hydroxyoestrone, 16-oxooestradiol-17β and 16-epioestriol. In addition, two dehydroxylation products, namely oestrone and oestradiol-17β were found. The metabolites formed from oestriol were partly conjugated to monoglucuronides, monosulphates and sulphoglucuronides. About 80% of the oestriol perfused was hydroxylated at C-atom 2. Most of the 2-hydroxyoestriol formed was either methylated (about 37%) or sulphated (about 55%). Only small amounts (less than 2%) of the catecholoestrogens formed were methylated as well as sulphated. The 2-hydroxyoestriol monosulphates accumulated in the liver. After their conjugation with glucuronic acid, the double conjugates formed were immediately excreted into the bile. In fact, 2-hydroxyoestriol 16α-monoglucuronide 2(3?)-monosulphate comprised by far the main biliary metabolite of [4-14C]oestriol, followed by oestriol 16α-monoglucuronide and 2-methoxyoestriol 16α-monoglucuronide. No tritiated sulphoglucuronides were detected, thus indicating that the monosulphates are the immediate precursors of the double conjugates. [6,9-3H2]Oestriol 16α-monoglucuronide was metabolised only to a small extent. After its uptake into the liver more than 90% of this conjugate was secreted unchanged into the bile. The remaining part was hydrolysed; the oestriol liberated followed the same metabolic reactions as those found for [4-14C]oestriol. This indicates that the 16α-glucuronide of oestriol is not metabolised to any appreciable extent.

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