scholarly journals Synthesis of phosphatidylethanolamine and ethanolamine plasmalogen by the CDP-ethanolamine and decarboxylase pathways in rat heart, kidney and liver

1991 ◽  
Vol 273 (1) ◽  
pp. 121-125 ◽  
Author(s):  
G Arthur ◽  
L Page
Keyword(s):  
Specific Radioactivity ◽  
Rat Tissues ◽  
Exchange Reactions ◽  
Base Exchange ◽  
Mammalian Cell Lines ◽  
Mammalian Tissues ◽  
Plasmalogen Content ◽  
Ethanolamine Plasmalogen

Studies with mammalian cell lines have led to suggestions that mammalian tissues may derive all of their phosphatidylethanolamine (PE) from the decarboxylation of phosphatidylserine (PS), and also that the physiological significance of the CDP-ethanolamine pathway was the synthesis of ethanolamine plasmalogen. We have therefore investigated the biosynthesis of PE and ethanolamine plasmalogen via the CDP-ethanolamine and decarboxylation pathways in vivo in three rat tissues (heart, kidney and liver), which differ in ethanolamine plasmalogen content. In all three tissues [14C]ethanolamine was incorporated into both PE and ethanolamine plasmalogen, whereas [3H]serine was incorporated into only PS and PE fractions. When [14C]ethanolamine was introduced into the animals, the specific radioactivity of ethanolamine plasmalogen in the kidney was always greater than that of the PE fraction; in the heart the specific radioactivity of the ethanolamine plasmalogen fraction was similar to that of the PE fraction, whereas in the liver the specific radioactivity of the PE fraction was always greater than that of the ethanolamine plasmalogen fraction. The results obtained in this study indicate that: (1) the CDP-ethanolamine pathway is utilized for the synthesis of both PE and ethanolamine plasmalogen in all three tissues; (2) the decarboxylation pathway is utilized solely for the synthesis of PE; (3) serine plasmalogens are not formed by base-exchange reactions; (4) the relative utilization of the CDP-ethanolamine pathway for the synthesis of PE and ethanolamine plasmalogen varies among tissues. Our studies also revealed that the hypolipidaemic drug MDL 29350 is a potent inhibitor of PE N-methyltransferase activity in vitro and in vivo.

scholarly journals Uptake of iodinated human kidney α-D-mannosidase by rat liver- Association with membrane elements and stability in vivo and in vitro

1976 ◽  
Vol 159 (3) ◽  
pp. 729-736 ◽  
Author(s):  
D V Marinković ◽  
S L Petrović ◽  
J V Martinović ◽  
J N Marinković
Keyword(s):  
Plasma Membranes ◽  
Specific Radioactivity ◽  
Human Kidney ◽  
Particulate Material ◽  
Enzymic Activity ◽  
Free Form ◽  
Rat Tissues ◽  
Liver And Kidney

1. Human kidney α-D-mannosidase (form A) was labelled with 125I to a specific radio-activity of approx. 2250muCi/mg of protein, essentially without loss of enzymic activity. The enzymic activity and radioactivity of the iodinated material also co-migrated in gel filtration and gel electrophoresis. 2. The binding of 125I-labelled mannosidase in vitro to particulate material in liver and kidney homogenates was of the other of 2 pg/mg of particulate material in liver and kidney homogenates was of the order of 2pg/mg of particulate protein withing 16h at 37 degrees C, and essentially zero in intervals of up to 60 min. The degradation in vitro of labelled exogenous mannosidase was of the order of 10-20pg/ 16th per mg of protein in postnuclear supernatant, and it was saturated entirely within 1h at 37 degrees C. 3. The binding of labelled mannosidase in vivo to particulate elements of liver homogenates 60 min after intravenous injection was at least 10 times higher in terms of specific radioactivity than the highest value attainable in vitro. Virtually all exogenous enzyme bound to liver particulate material could be recovered in macromolecular form after disruption of membranes by detergents. 4. The radioactive enzyme bound to liver particulate material could be detached almost completely by shearing, repeated freezing and thawing, and exposure to strong detergents under conditions that do not eliminate rough-endoplasmic-membrane structure. It could bot be released, however, by high salt concentration (0.5M-KC1) or by exposure to weak detergents such as Tween 80. The particle-bound enzyme should thus be associated with plasma membranes and lysosome-like elements. 5. Of the rat tissues studied, only liver could approach, within 60 min after the injection, the concentration of exogenous mannosidase found in the blood serum. The activity per g tissue weight fell progressively from liver (60% of serum value) to kidney (16% of serum value), lung (8% of serum vlaue), spleen (6% of serum value) and brain (0.9% of serum value). Most of the radioactive enzyme found in tissues other than liver appeared to be present in a free form, whereas in liver more than 50% of the labelled enzyme was associated with membrane elements.

Radiolabeling of Fibrinogen Using the Iodogen Technique

1981 ◽  
Vol 46 (03) ◽  
pp. 593-596 ◽  
Author(s):  
Linda C Knight ◽  
Andrei Z Budzynski ◽  
Stephanie A Olexa
Keyword(s):  
Specific Radioactivity ◽  
Oxidizing Agent ◽  
Iodine Monochloride ◽  
Human Fibrinogen

SummaryThe properties of human fibrinogen labeled with 125-Iodine using Iodogen (1, 3, 4, 6-tetrachloro-3α, 6α-diphenylglycoluril) as an oxidizing agent were compared with those of an iodine monochloride labeled counterpart. It was found that thrombin clottability, binding to staphylococci, the relative specific radioactivity of the Aα, Bβ, and γ chains and in vivo clearance from plasma in rabbits were the same in these two labeled fibrinogen preparations. Labeling efficiency was higher when iodogen was used. It is concluded that human fibrinogen labeled with radioiodine using the Iodogen technique is suitable for studies in vitro and in vivo.

EPA-enriched ethanolamine plasmalogen and EPA-enriched phosphatidylethanolamine enhance BDNF/TrkB/CREB signaling and inhibit neuronal apoptosis in vitro and in vivo

2020 ◽  
Vol 11 (2) ◽  
pp. 1729-1739 ◽  
Author(s):  
Hongxia Che ◽  
Lingyu Zhang ◽  
Lin Ding ◽  
Wancui Xie ◽  
Xiaoming Jiang ◽  
...  
Keyword(s):  
Learning And Memory ◽  
Neuronal Apoptosis ◽  
Memory Deficit ◽  
Ethanolamine Plasmalogen ◽  
Learning And Memory Deficit

Our previous study showed that EPA-enriched ethanolamine plasmalogen (EPA-pPE) exerted more significant effects than EPA-enriched phosphatidylethanolamine (EPA-PE) in improving learning and memory deficit.

THE INCORPORATION OF PALMITATE-1-14C BY RAT LUNG IN VITRO

1967 ◽  
Vol 45 (4) ◽  
pp. 597-607 ◽  
Author(s):  
A. Naimark ◽  
D. Klass
Keyword(s):  
Specific Activity ◽  
Specific Radioactivity ◽  
Phosphatidyl Inositol ◽  
Phosphatidyl Serine ◽  
Rat Lung ◽  
Exchange Reactions ◽  
Ethanolamine Phosphatidyl ◽  
Exogenous Glucose ◽  
Lipid Fractions

The incorporation of palmitate-1-14C into various lipid fractions was studied in rat lung in vitro. Most of the radioactivity was found in phospholipid, although in terms of decreasing specific activity the lipids were ranked: free fatty acid (FFA), glycerides, phospholipid. In addition to the usual glycerophosphatides, rat lung contained a substance with some of the chromatographic characteristics of phosphatidyl dimethylethanolamine. In terms of decreasing specific activities the phospholipids were ranked: phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl dimethylethanolamine, phosphatidyl serine plus phosphatidyl inositol, sphingomyelin plus lysophosphatidyl choline. Inhibition of oxidative energy production by hypoxia, cyanide, or low temperature markedly depressed the esterification of palmitate-1-14C. Less marked depression was observed in the absence of exogenous glucose. In all cases the decreased incorporation was associated with an increase in the total and specific radioactivity in tissue FFA. It is concluded that energy-independent exchange reactions are probably of little importance in the incorporation of FFA into esterified lipids of lung tissue. Under conditions of metabolic inhibition the penetration of labelled FFA into the tissue FFA pool does not appear to limit esterification.

THE BINDING OF [1,2-3H]TESTOSTERONE WITHIN NUCLEI OF THE RAT PROSTATE

1969 ◽  
Vol 44 (3) ◽  
pp. 323-333 ◽  
Author(s):  
W. I. P. MAINWARING
Keyword(s):  
Molecular Weight ◽  
Equilibrium Dialysis ◽  
Prostate Gland ◽  
Ventral Prostate ◽  
Rat Tissues ◽  
Receptor Complex ◽  
Rat Prostate ◽  
Binding Component

SUMMARY The specificity of the binding of [1,2-3H]testosterone to nuclei of various rat tissues in vivo has been studied. A significant amount of radioactivity was retained in the nuclei of androgen-dependent tissues only, particularly the ventral prostate gland. The bound radioactivity was only partially recovered as [1,2-3H]testosterone; the remainder was identified as [3H]5α-dihydrotestosterone. Efforts were made to characterize the binding component, or 'receptor', in prostatic nuclei. On digestion of nuclei labelled in vivo with [1,2-3H]testosterone, with enzymes of narrow substrate specificity, only trypsin released tritium, suggesting that the receptor is a protein. On the basis of subfractionation studies of labelled nuclei, the receptor is an acidic protein. The androgen—receptor complex could be effectively extracted from the prostatic nuclei in 1 m-NaCl and from the results of fractionations on a calibrated agarose column, the complex has a molecular weight 100,000–120,000. The specificity of the binding of steroids to such 1 m-NaCl extracts in vitro was investigated by the equilibrium dialysis procedure. Under these conditions, the specificity of the binding of [1,2-3H]testosterone demonstrated in vivo could not be simulated. The receptor is probably part of the chromatin complex but its precise intranuclear localization cannot be determined by biochemical procedures alone.

scholarly journals Enhanced phosphorylation of Na+–Cl− co-transporter in experimental metabolic syndrome: role of insulin

2012 ◽  
Vol 123 (11) ◽  
pp. 635-647 ◽  
Author(s):  
Radko Komers ◽  
Shaunessy Rogers ◽  
Terry T. Oyama ◽  
Bei Xu ◽  
Chao-Ling Yang ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Time Course ◽  
Kinase Inhibitor ◽  
Endogenous Expression ◽  
The Metabolic Syndrome ◽  
Mammalian Cell Lines ◽  
Phosphoinositide 3 Kinase

In the present study, we investigated the activity of the thiazide-sensitive NCC (Na+–Cl− co-transporter) in experimental metabolic syndrome and the role of insulin in NCC activation. Renal responses to the NCC inhibitor HCTZ (hydrochlorothiazide), as a measure of NCC activity in vivo, were studied in 12-week-old ZO (Zucker obese) rats, a model of the metabolic syndrome, and in ZL (Zucker lean) control animals, together with renal NCC expression and molecular markers of NCC activity, such as localization and phosphorylation. Effects of insulin were studied further in mammalian cell lines with inducible and endogenous expression of this molecule. ZO rats displayed marked hyperinsulinaemia, but no differences in plasma aldosterone, compared with ZL rats. In ZO rats, natriuretic and diuretic responses to NCC inhibition with HCTZ were enhanced compared with ZL rats, and were associated with a decrease in BP (blood pressure). ZO rats displayed enhanced Thr53 NCC phosphorylation and predominant membrane localization of both total and phosphorylated NCC, together with a different profile in expression of SPAK (Ste20-related proline/alanine-rich kinase) isoforms, and lower expression of WNK4. In vitro, insulin induced NCC phosphorylation, which was blocked by a PI3K (phosphoinositide 3-kinase) inhibitor. Insulin-induced reduction in WNK4 expression was also observed, but delayed compared with the time course of NCC phosphorylation. In summary, we report increased NCC activity in hyperinsulinaemic rodents in conjunction with the SPAK expression profile consistent with NCC activation and reduced WNK4, as well as an ability of insulin to induce NCC stimulatory phosphorylation in vitro. Together, these findings indicate that hyperinsulinaemia is an important driving force of NCC activity in the metabolic syndrome with possible consequences for BP regulation.

A Study on the Possible Occurrence of Base-Exchange Reactions in Vivo

1978 ◽  
pp. 319-325 ◽  
Author(s):  
P. Orlando ◽  
G. Arienti ◽  
P. Saracino ◽  
L. Corazzi ◽  
P. Massari ◽  
...  
Keyword(s):  
Exchange Reactions ◽  
Base Exchange

scholarly journals The metabolism of polyphosphoinositides in hen brain and sciatic nerve

1969 ◽  
Vol 111 (2) ◽  
pp. 157-165 ◽  
Author(s):  
A. Sheltawy ◽  
R. M. C. Dawson
Keyword(s):  
Sciatic Nerve ◽  
Previous Investigation ◽  
Relative Rate ◽  
Specific Radioactivity ◽  
Brain Slices ◽  
Soluble Phosphorus ◽  
Ethanolamine Plasmalogen ◽  
32P Incorporation ◽  
The Brain

1. The distribution of individual phospholipids was determined in hen brain and compared with that in sciatic nerve obtained in a previous investigation. Sciatic nerve is more enriched in the myelinic phospholipids ethanolamine plasmalogen, phosphatidylserine and sphingomyelin, but it contains relatively less triphosphoinositide, and much less diphosphoinositide, than the brain. 2. The course of incorporation of intraperitoneally injected 32P into the acid-soluble phosphorus, phosphoinositides and total phospholipids of hen brain and sciatic nerve was followed. Although the maximum specific radioactivity in sciatic nerve of acid-soluble phosphorus is 4·5 times, and that of triphosphoinositide six times, that in the brain, the relative rate of triphosphoinositide phosphorus synthesis per gram of brain is three times that in sciatic nerve. 3. Administration of the demyelinating agent tri-o-cresyl phosphate to hens has no significant effect on the amounts or the rate of 32P incorporation into the total phospholipids of the sciatic nerve. However, the rate of incorporation of 32P into triphosphoinositide, although not its concentration, is raised from the first day after administration of the drug and remains thus 13 and 23 days later. 4. The incorporation of 32P into polyphosphoinositides of hen brain slices in vitro was studied. The recovery of triphosphoinositide from the slices is markedly increased in the presence of EDTA, although the rate of incorporation of 32P is unaffected. The incorporation of 32P is dependent on the presence of Mg2+ and Ca2+ in the medium, and is decreased when Na+ is replaced with K+ or cholinium ions.

scholarly journals Some biochemical effects of triamcinolone acetonide on rat liver and muscle

1970 ◽  
Vol 116 (3) ◽  
pp. 349-355 ◽  
Author(s):  
R. F. Peters ◽  
M. C. Richardson ◽  
Margaret Small ◽  
A. M. White
Keyword(s):  
Amino Acids ◽  
Triamcinolone Acetonide ◽  
Time Course ◽  
Muscle Protein ◽  
Specific Radioactivity ◽  
Synthetic Activity ◽  
Tissue Homogenate ◽  
Glycogen Concentration

1. The powerful anti-inflammatory glucocorticoid triamcinolone acetonide, administered to rats at 20 and 2.5mg/kg, leads to a decrease in the incorporation in vivo of [3H]uridine and [32P]orthophosphate into hind-limb skeletal muscle. 2. At the higher dose, this decrease in the rate of incorporation of precursors into RNA precedes a decrease in the incorporating ability of muscle ribosomes, which commences about 4–5h after drug administration, but is unaccompanied by any changes in the concentration of tissue ATP or free amino acids. 3. The ribosomal dysfunction extends to polyribosomes, which can only be successfully isolated from the muscle of triamcinolone-treated animals after the addition of α-amylase to the tissue homogenate to remove glycogen. 4. The specific radioactivity of muscle protein labelled in vivo with 14C-labelled amino acids does not decrease progressively after triamcinolone administration. After 2h there is an apparent stimulation of incorporation which leads to an overall discrepancy between measurements of protein-synthetic activity made in vivo and in vitro. 5. There is a significant increase in muscle-glycogen concentration between 8 and 12h after the administration of triamcinolone acetonide (20mg/kg), although a significant decrease occurs after 4h. The fall in glycogen concentration may be due to a decrease in the rate of synthesis of protein essential for glucose uptake into the tissues. 6. As judged by (a) incorporation of 14C-labelled amino acids into protein, (b) [3H]uridine and [32P]-orthophosphate incorporation into RNA, (c) the rate of induction of tryptophan pyrrolase and (d) changes in the pool sizes of taurine and tryptophan, the responses in liver followed the same time-course as those in muscle after administration of the drug.

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