The Occurrence of Folate-Derived Pteridines in Rat Liver

1978 ◽  
Vol 54 (4) ◽  
pp. 355-360
Author(s):  
Berenice Reed ◽  
D. Weir ◽  
J. Scott
Keyword(s):  
Rat Liver ◽  
Brain Metabolism ◽  
Radioactive Tracer ◽  
The Other ◽  
Other Hand

1. It has previously been shown that folate polyglutamates in the rat are catabolized almost exclusively via cleavage of the C-9—N-10 bond, resulting in the formation of pteridines and p-aminobenzoylglutamate. The latter catabolite is rapidly excreted, appearing in the urine as acetamidobenzoylglutamate and is undetectable in rat liver. 2. The pteridines catabolites on the other hand are retained to a much greater extent by the liver, forming an ever-increasing proportion of the retained radioactive tracer. 3. A possible role for these pteridines as cofactors in brain metabolism is discussed.

scholarly journals Effects of di-isopropyl phosphorofluoridate on rat liver microsomal and lysosomal β-glucuronidase

1977 ◽  
Vol 164 (3) ◽  
pp. 549-556 ◽  
Author(s):  
Brian Mandell ◽  
Philip Stahl
Keyword(s):  
Rat Liver ◽  
Early Time ◽  
Subcellular Fractionation ◽  
Isolated Hepatocytes ◽  
The Other ◽  
Time Points ◽  
Glucuronidase Activity ◽  
Other Hand ◽  
Microsomal Membranes

iPr2P-F (di-isopropyl phosphorofluoridate) administration to rats produces a liver-dependent specific elevation of plasma β-glucuronidase activity. The response is unaffected by puromycin pretreatment. By using subcellular-fractionation techniques, the rise in plasma β-glucuronidase activity was correlated temporally with a fall in liver microsomal β-glucuronidase activity. After iPr2P-F treatment, liver microsomal membranes are depleted of β-glucuronidase but slowly return to normal over 1 week. On the other hand, liver lysosomal β-glucuronidase activity is high at early time points (less than 60min) after iPr2P-F administration but decreases to below control values; this lasts for a few days. The response to iPr2P-F was demonstrated in isolated hepatocytes prepared from iPr2P-F-treated rats. In such preparations, microsomal β-glucuronidase is lost rapidly, followed by a specific decrease in hepatocyte lysosomal β-glucuronidase. The results suggest that a pool of microsomal β-glucuronidase serves as precursor to plasma β-glucuronidase in iPr2P-F-treated rats, and further, that microsomal β-glucuronidase may serve as precursor to lysosomal β-glucuronidase.

scholarly journals The stereochemistry of hydrogen elimination from C-7 in cholesterol and ergosterol biosynthesis

1970 ◽  
Vol 117 (3) ◽  
pp. 539-542 ◽  
Author(s):  
M. Akhtar ◽  
A. D. Rahimtula ◽  
D. C. Wilton
Keyword(s):  
Hydrogen Atom ◽  
Rat Liver ◽  
The Other ◽  
Yeast Cells ◽  
Ergosterol Biosynthesis ◽  
Hydrogen Atoms ◽  
Hydrogen Elimination ◽  
Other Hand

The synthesis of [7α-3H]lanosterol is described. It is shown that in the conversion of [7α-3H,26,27-14C2]lanosterol into cholesterol by a rat liver system, it is the 7β-hydrogen atom that is predominantly removed. On the other hand, the conversion of doubly labelled lanosterol into ergosterol by whole yeast cells results in the loss of the 7α-hydrogen atom. These results therefore suggest that the C-7 hydrogen atoms with opposite stereochemistry are labilized by the rat liver and the yeast Δ8–Δ7 steroid isomerases.

Lipogenesis from ketone bodies in the perfused rat liver: effects of acetate and ethanol

1987 ◽  
Vol 65 (11) ◽  
pp. 989-996 ◽  
Author(s):  
Gerda Endemann ◽  
Patrick G. Goetz ◽  
John F. Tomera ◽  
William M. Rand ◽  
Sylvain Desrochers ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Rat Liver ◽  
Ketone Body ◽  
Ketone Bodies ◽  
The Other ◽  
Ethanol Metabolism ◽  
Perfused Rat Liver ◽  
Other Hand

The interactions between acetate or ethanol metabolism, lipogenesis, and ketone body utilization have been studied in isolated livers from fed rats perfused with 15 mM glucose and 10 mM acetate or ethanol. The contribution of acetate to ketogenesis is constant; on the other hand, the contribution of ethanol to ketogenesis increases with time, presumably because of the accumulation of acetate in the perfusate. Ketogenesis is decreased in the presence of ethanol (but not acetate), while ketone body utilization is not affected by ethanol or acetate. Acetate contributes one third and ethanol contributes one half of the carbon incorporated into fatty acids and 3-β-hydroxysterols. Only a small fraction (less than 5%) of the incorporation of acetate or ethanol into fatty acids and sterols occurs via transient incorporation into ketone bodies.

BIOGENESE VON ÖSTRIOL-3-MONOGLUCURONID

1967 ◽  
Vol 56 (3) ◽  
pp. 403-412 ◽  
Author(s):  
K. Dahm ◽  
Monika Lindlau ◽  
H. Breuer
Keyword(s):  
Rat Liver ◽  
Steric Hindrance ◽  
Microsomal Fraction ◽  
Enzyme System ◽  
The Other ◽  
Human Intestine ◽  
Enzyme Preparations ◽  
Other Hand ◽  
Enzymatic Reduction

ABSTRACT The biogenesis of oestriol 3-monoglucuronide has been studied using different enzyme preparations of human intestine and placenta as well as of rat liver. After incubation of oestriol with the microsomal fraction of human intestine, oestriol 3-monoglucuronide was found in addition to oestriol 16α-monoglucuronide and oestriol 17β-monoglucuronide. No oestriol 3-monoglucuronide was found when 16α-hydroxyoestrone 3-monoglucuronide, prepared biosynthetically, was incubated with a 24-fold purified human placental 17β-hydroxysteroid:NAD-oxidoreductase. On the other hand, no oestriol 3-monoglucuronide was formed when 17β-oestradiol 3-monoglucuronide was subjected to the action of the microsomal 16α-hydroxylase of rat liver. These results may be explained by steric hindrance of the enzyme system involved. On the basis of the present findings it can be concluded that oestriol 3-monoglucuronide arises exclusively by direct glucuronidation of oestriol, and not by enzymatic reduction of 16α-hydroxyoestrone 3-monoglucuronide or by 16α-hydroxylation of 17β-oestradiol 3-monoglucuronide.

scholarly journals Effect of stirring during fixation upon immunofluorescence. Results with distribution of albumin-producing cells in liver.

1976 ◽  
Vol 24 (8) ◽  
pp. 926-932 ◽  
Author(s):  
M Horikawa ◽  
N Chisaka ◽  
S Yokoyama ◽  
T Onoé
Keyword(s):  
Rat Liver ◽  
The Other ◽  
Magnetic Stirrer ◽  
Other Hand ◽  
Rapid Fixation ◽  
Protein Free Diet

When the immunofluroscent study on the distribution and the incidence of albumin-producing hepatocytes in the rat liver was performed by the method of Sainte-Marie, the number of positive cells showed various values (10-60%). It was surmised that when the permeability of the fixative was delayed, albumin had flowed out from the cytoplasm of the unfixed hepatocytes. By the simple means of constant stirring of the fixative using a magnetic stirrer, we accomplished rapid fixation and achieved results in which positive cells attained 100%. On the other hand, the incidence of positive cells decreased markedly when rats were fed a protein-free diet.

Effect of 5′-Terminated (2′— 5′)-01igoadenylates on Cap Degrading Activities in Rat Liver Nuclei

1983 ◽  
Vol 38 (7-8) ◽  
pp. 631-634 ◽  
Author(s):  
Winfried Michels ◽  
Eckhard Schlimme
Keyword(s):  
Synergistic Effect ◽  
Rat Liver ◽  
Cellular Metabolism ◽  
The Other ◽  
Rat Liver Nuclei ◽  
Other Hand ◽  
Infected Cells ◽  
Liver Nuclei ◽  
Exonucleolytic Degradation

(2'-5')-oligoadenylates bearing a 5'-terminal triphosphate or a 5'GTP-group inhibit the activity of a dinucleoside triphosphatase in rat liver nuclei thereby protecting mRNA against 5'-exonucleolytic degradation. (2'-5')-oligoadenylates, on the other hand, were known to enhance the activity of an endoribonuclease, RNaseF. Thus a synergistic effect may be assumed in vivo, i.e. cellular metabolism seems to be protected twice in virus-infected cells.

Effect of 3,3′-di-iodothyronine and 3,5-di-iodothyronine on rat liver mitochondria

1993 ◽  
Vol 136 (1) ◽  
pp. 59-64 ◽  
Author(s):  
A. Lanni ◽  
M. Moreno ◽  
M. Cioffi ◽  
F. Goglia
Keyword(s):  
Cytochrome Oxidase ◽  
Rat Liver ◽  
Oxidase Activity ◽  
Mitochondrial Protein ◽  
The Other ◽  
Rat Liver Mitochondria ◽  
Mitochondrial Activity ◽  
Mitochondrial Mass ◽  
Cytochrome Oxidase Activity ◽  
Other Hand

ABSTRACT In the present study we report that 3,3′,5-tri-iodothyronine (T3) as well as two iodothyronines (3,5-diiodothyronine (3,5-T2) and 3,3′-di-iodothyronine (3,3′-T2)) significantly influence rat liver mitochondrial activity. Liver oxidative capacity (measured as cytochrome oxidase activity/g wet tissue) in hypothyroid compared with normal rats was significantly reduced (21%, P > 0·01) and the administration of T3 and both iodothyronines restored normal values. At the mitochondrial level, treatment with T3 stimulated respiratory activity (state 4 and state 3) and did not influence cytochrome oxidase activity. On the other hand, both the mitochondrial respiratory rate and specific cytochrome oxidase activity significantly increased in hypothyroid animals after treatment with 3,3′-T2 or 3,5-T2 (about 50 and 40% respectively). The actions of both iodothyronines were rapid and evident by 1 h after the injection. The hepatic mitochondrial protein content which decreased in hypothyroid rats (9·6 mg/g liver compared with 14·1 in normal controls, P < 0·05) was restored by T3 injection, while neither T2 was able to restore it. Our results suggest that T3 and both iodothyronines have different mechanisms of action. T3 acts on both mitochondrial mass and activity; the action on mitochondrial activity was not exerted at the cytochrome oxidase complex level. The action of the iodothyronines, on the other hand, is exerted directly on the cytochrome oxidase complex without any noticeable action on the mitochondrial mass. Journal of Endocrinology (1993) 136, 59–64

scholarly journals Amino Acid-Containing Krebs-Henseleit Buffer Protects Rat Liver in a Long-Term Organ Perfusion Model

2018 ◽  
Vol 24 (3) ◽  
pp. 168-179
Author(s):  
Reza Heidari ◽  
Mohammad Mehdi Ommati ◽  
Sanya Alahyari ◽  
Negar Azarpira ◽  
Hossein Niknahad
Keyword(s):  
Lipid Peroxidation ◽  
Amino Acid ◽  
Liver Injury ◽  
Rat Liver ◽  
The Body ◽  
The Other ◽  
Control Group ◽  
Organ Perfusion ◽  
Other Hand ◽  
Krebs Henseleit Buffer

Background: The liver is vulnerable to the toxicity induced by xenobiotics. On the other hand, it has been found that several endogenously-found amino acids have hepatoprotective properties. The current study was designed to evaluate the effect of taurine, glycine, and histidine on the liver function in an ex vivo model of prolonged organ perfusion. Methods: Rat liver was isolated and perfused with a hemoglobin- and albumin-free Krebs‑Henseleit buffer (KBH). Liver injury biomarkers were monitored at scheduled time intervals. Results: The perfusate level of lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and the potassium ion (K+) were gradually increased in control (Only KBH) group. The histopathological evaluation also revealed significant necrosis, sinusoidal dilation, and pyknosis in control liver. Moreover, significant increase in lipid peroxidation and depletion of hepatic glutathione stores were detected in the control group. It was found that taurine (5, 10 and 20 mM) and glycine (5, 10 and 20 mM)-containing KBH buffer significantly decreased the perfusate level of liver injury biomarkers. Furthermore, lower liver tissue pathological changes, decreased lipid peroxidation, and higher glutathione content was detected in amino acid-treated groups. Histidine administration showed no significant protective effect on liver injury in the current study. On the other hand, combination amino acid administration (glycine and taurine) showed a better hepatoprotective profile. Conclusion: The data obtained from the current study might help to provide safe hepatoprotective agents against xenobiotics-induced hepatotoxicity or preserve liver functionality outside the body.

Effect of growth hormone and hydrocortisone on the synthesis of rapidly labeled, high molecular weight, nuclear RNA in rat liver

1969 ◽  
Vol 47 (2) ◽  
pp. 226-229 ◽  
Author(s):  
Maurice Brossard ◽  
Louis Nicole
Keyword(s):  
Molecular Weight ◽  
Growth Hormone ◽  
High Molecular Weight ◽  
Rat Liver ◽  
Orotic Acid ◽  
The Other ◽  
Other Hand ◽  
Nuclear Rna ◽  
Nucleolar Rna

The effects of growth hormone and hydrocortisone on the synthesis of rat liver RNA have been studied. Administration of growth hormone stimulated the incorporation of 14C-orotic acid into 45 S preribosomal nucleolar RNA, and had no effect on the 6–50 S polydisperse nuclear RNA of extra-nucleolar origin. On the other hand, hydrocortisone stimulated the synthesis of all types of nuclear RNA, but mainly that of the 18 S class of 6–50 S polydisperse nuclear RNA.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

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