N-Acetyl-l-cysteine abolishes the bromoethylamine-induced choline incorporation into renal papillary tissue

1995 ◽  
Vol 10 (5) ◽  
pp. 251-257 ◽  
Author(s):  
L. E. Thielemann ◽  
R. A. Rodrigo ◽  
E. W. Oberhauser ◽  
G. Rosenblut ◽  
L. A. Videla
Keyword(s):  
Choline Incorporation

Fetal Lung Lecithin Metabolism in the Glucose-Intolerant Rhesus Monkey Pregnancy

PEDIATRICS ◽  
1976 ◽  
Vol 57 (5) ◽  
pp. 722-728
Author(s):  
Michael F. Epstein ◽  
Phillip M. Farrell ◽  
Ronald A. Chez
Keyword(s):  
Rhesus Monkey ◽  
Glucose Intolerance ◽  
Mode Of Delivery ◽  
Fetal Lung ◽  
Late Gestation ◽  
Control Groups ◽  
Choline Incorporation ◽  
Acid Base Status ◽  
Two Measures ◽  
Maternal Glucose

Fetal lung lecithin metabolism was examined in rhesus monkey gestations complicated by glucose intolerance secondary to maternal streptozotocin (STZ) administration. Fetuses of STZ-treated mothers were delivered at 85% to 89% of term and were compared to two control groups of fetuses from normal pregnancies—one group age-matched to the STZ pregnancies, and the other composed of fetuses delivered in the final 10% of gestation. In the glucose-intolerant pregnancies, two measures of fetal lung lecithin biosynthesis—the amniotic fluid lecithin-to-sphingomyelin (L/S) ratio and the rate of 14C-choline incorporation into lecithin in fetal lung slices—were significantly greater than in age-matched normal gestations and were similar to results in late-gestation controls. However, lung lecithin concentrations in the glucose-intolerant group were comparable to the age-matched controls, and both were significantly less than in the late-gestation controls. Since the gestational age, mode of delivery, and fetal acid-base status were the same in the age-matched groups, we conclude that these changes in fetal lung lecithin metabolism are due to the effects of maternal glucose intolerance.

scholarly journals Channelling of intermediates in the biosynthesis of phosphatidylcholine and phosphatidylethanolamine in mammalian cells

1998 ◽  
Vol 334 (3) ◽  
pp. 511-517 ◽  
Author(s):  
Bellinda A. BLADERGROEN ◽  
Math J. H. GEELEN ◽  
A. Ch. Pulla REDDY ◽  
Peter E. DECLERCQ ◽  
Lambert M. G. VAN GOLDE
Keyword(s):  
Staphylococcus Aureus ◽  
Mammalian Cells ◽  
Glioma Cells ◽  
Rat Hepatocytes ◽  
Cell Types ◽  
General Phenomenon ◽  
Rat Glioma ◽  
Permeabilized Cells ◽  
Metabolic Compartmentation ◽  
Choline Incorporation

Previous studies with electropermeabilized cells have suggested the occurrence of metabolic compartmentation and Ca2+-dependent channeling of intermediates of phosphatidylcholine (PC) biosynthesis in C6 rat glioma cells. With a more accessible permeabilization technique, we investigated whether this is a more general phenomenon also occurring in other cell types and whether channeling is involved in phosphatidylethanolamine (PE) synthesis as well. C6 rat glioma cells, C3H10T½ fibroblasts and rat hepatocytes were permeabilized with Staphylococcus aureus α-toxin, and the incorporation of the radiolabelled precursors choline, phosphocholine (P-choline), ethanolamine and phosphoethanolamine (P-EA) into PC and PE were measured both at high and low Ca2+ concentrations. In glioma cells, permeabilization at high Ca2+ concentration did not affect [14C]choline or [14C]P-choline incorporation into PC. However, reduction of free Ca2+ in the medium from 1.8 mM to < 1 nM resulted in a dramatic increase in [14C]P-choline incorporation into permeabilized cells, whereas [14C]choline incorporation remained unaffected. Also, in fibroblasts, reduction of extracellular Ca2+ increased [14C]P-choline and [14C]P-EA incorporation into PC and PE respectively. In hepatocytes, a combination of α-toxin and low Ca2+ concentration severely impaired [14C]choline incorporation into PC. Therefore, α-toxin-permeabilized hepatocytes are not a good model in which to study channeling of intermediates in PC biosynthesis. In conclusion, our results indicate that channeling is involved in PC synthesis in glioma cells and fibroblasts. PE synthesis in fibroblasts is also at least partly dependent on channeling.

Effect of thiocarbamate, urea, and uracil herbicides on lipid metabolism in groundnut (Arachis hypogaea) leaves

1990 ◽  
Vol 68 (2) ◽  
pp. 567-573 ◽  
Author(s):  
R. Rajasekharan ◽  
P. S. Sastry
Keyword(s):  
Lipid Metabolism ◽  
Arachis Hypogaea ◽  
Acid Synthesis ◽  
Inhibitory Effect ◽  
Significant Inhibition ◽  
The Other ◽  
Acetate Incorporation ◽  
Phosphatidic Acid Phosphatase ◽  
Choline Incorporation ◽  
Plant Lipids

The effect of thiocarbamates (S-ethyldipropylthiocarbamate and diallate), substituted ureas (monuron and diuron), and uracils (bromacil and terbacil) on lipid metabolism in groundnut (Arachis hypogaea) leaves was investigated under nonphotosynthetic conditions. The uptake of [1-14C]acetate by leaf disks was inhibited by the thiocarbamates and marginally by the substituted ureas, but not by the uracil herbicides. The uptake of [methyl-14C]choline was inhibited to a lesser extent by thiocarbamates, while the other herbicides showed a slight stimulation. The thiocarbamates almost completely inhibited uptake of [32P]orthophosphate at 1.0 mM concentration, while diuron and terbacil showed significant inhibition. [1-14C]Acetate incorporation into lipids was inhibited only by diallate. [methyl-14C]Choline incorporation into the choline phosphoglycerides was inhibited by diallate, diuron, and bromacil. The incorporation of [32P]orthophosphate into phospholipids was substantially inhibited (over 90% at 1.0 mM) by the thiocarbamates, but not by the other herbicides. [35S]Sulfate incorporation into sulfoquinovosyl diglycerides was markedly inhibited only by the thiocarbamates. Fatty acid synthesis by isolated chloroplasts was inhibited 40–85% by thiocarbamates, substituted ureas, and bromacil, but not by terbacil. The inhibitory effect of the urea derivatives was reversible, but that of thiocarbamates was irreversible. sn-Glycerol-3-phosphate acyltransferase(s) of the chloroplast and microsomal fractions were profoundly inhibited by thiocarbamates, but not by the other two groups of herbicides. Phosphatidic acid phosphatase was insensitive to all the herbicides tested.Key words: herbicides, thiocarbamates, substituted ureas, uracils, effects on plant lipids.

Independence of onset of compensatory kidney growth from changes in renal function

1976 ◽  
Vol 230 (4) ◽  
pp. 1067-1071 ◽  
Author(s):  
AI Katz ◽  
FG Toback ◽  
MD Lindheimer
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Filtration Rate ◽  
Compensatory Growth ◽  
Sodium Reabsorption ◽  
Sham Operation ◽  
Kidney Growth ◽  
Choline Incorporation ◽  
Glomerular Filtrate ◽  
Cortical Slices

Renal function was measure before and shortly after uninephrectomy in mice to evaluate if work expended in the reabsorption of glomerular filtrate plays a role in the initiation of compensatory growth. To exclude the possibility of small but undetectable increments in glomerular filtration rate and absolute sodium reabsorption these functions were experimentally reduced immediately after uninephrectomy and sham nephrectomy. The onset of growth was indicated by an increased rate of [14C]choline incorporation into phospholipid in renal cortical slices. [14C]choline incorporation increased significantly only after uninephrectomy and remained unchanged after sham operation regardless of the magnitude or direction of the concurrent change in sodium reabsorption. The rate of incorporation increased by 40 +/- 8% (P less than 0.005) in uninephrectomized animals whose sodium reabsorption was reduced by 34 +/- 6% (P less than 0.001) and rose 45 +/- 11% (P less than 0.005) when sodium reabsorption remained unchanged. These results indicate that compensatory kidney growth is not triggered by an increase in renal work expended in the reabsorption of glomerular filtrate; in fact, it can occur when reabsorptive work is substantially decreased.

Sinapine as a Supply of Choline for the Biosynthesis of Phosphatidylcholine in Raphanus sativus Seedlings

1981 ◽  
Vol 36 (3-4) ◽  
pp. 215-221 ◽  
Author(s):  
Dieter Strack
Keyword(s):  
Raphanus Sativus ◽  
High Performance ◽  
High Performance Liquid Chromatographic ◽  
Fatty Acyl ◽  
Degree Of Unsaturation ◽  
Choline Incorporation ◽  
Immature Seeds ◽  
Free Choline ◽  
Liquid Chromatographic ◽  
Hydrolysis Of

Biosynthesis of phosphatidylcholine in young seedlings of Raphanus sativus is supplied with choline from degradation of the seed constituent sinapine (sinapoylcholine). This conclusion has been deduced from the following results: (1) Raphanus sativus seedlings accumulate approx. 70 nmol phosphatidylcholine which may be relevant for the consumption of choline, liberated during hydrolysis of approx. 130 nmol sinapine. (2) [14C]choline and [14C]ethanolamine, taken up by germinating Raphanus seeds, are exclusively consumed in the biosynthesis of phosphatidylcholine and phosphatidylethanolamine, respectively. (3) Pulse-chase experiments with seedlings at different germination stages show a reduced [14C]choline incorporation into phosphatidylcholine at the time when degradation of sinapine occurs, obviously as a result of an isotope dilution by an increase of the endogenous choline pool. (4) After [14C]choline pulse to immature seeds, during the process of seed maturation most of the activity taken up is incorporated into accumulating sinapine and approx. 50% compared to this into phosphatidylcholine. During seedling development the quantity of labelled sinapine rapidly decreases as a result of sinapine degradation with a concomitant label increase in free choline, phosphorylcholine, and phosphatidylcholine. Approx. 50% of the choline liberated from sinapine, is consumed in the biosynthesis of phosphatidylcholine. High performance liquid chromatographic analyses of phosphatidylcholine during Raphanus germination revealed that this phospholipid might be a metabolically active compound. Changes in the absorptivity of this compound at 210 nm indicate changes in the degree of unsaturation in the fatty acyl groups

scholarly journals OSMOTIC REGULATION OF α-AMYLASE SYNTHESIS AND POLYRIBOSOME FORMATION IN ALEURONE CELLS OF BARLEY

1973 ◽  
Vol 59 (2) ◽  
pp. 444-455 ◽  
Author(s):  
Judith E. Armstrong ◽  
Russell L. Jones
Keyword(s):  
Water Stress ◽  
Marked Decrease ◽  
Gradient Centrifugation ◽  
Sucrose Density Gradient ◽  
Hordeum Vulgare L ◽  
Sucrose Density Gradient Centrifugation ◽  
Total Rna ◽  
Aleurone Cells ◽  
Choline Incorporation ◽  
Stressed Cells

Water stress inhibits the gibberellic acid (GA3)-induced synthesis of α-amylase in aleurone layers of barley (Hordeum vulgare L.). Electron microscope evidence indicates that the effect of water stress induced by 0.6 M solutions of polyethylene glycol (PEG) is to reduce the binding of ribosomes to the endoplasmic reticulum. This was confirmed by sucrose density gradient centrifugation of polyribosome preparations from stressed cells. The reduction in polyribosome formation does not result from reduced ribosome activity as measured by [3H]peptidylpuromycin formation. Thus, calculation of percent active ribosomes shows that osmoticum has little effect on the ability of ribosomes to incorporate puromycin into nascent protein. Water stress does not cause a marked decrease in the total RNA level of aleurone cells. Estimates of total RNA in postmitochondrial supernatant fractions from stressed cells show only a reduction of 8–9% relative to the control. Membrane synthesis measured by [14C]choline incorporation is depressed by 15% in cells stressed with 0.6 M PEG for 2.5 hours.

Lysosomal-type PLA2and turnover of alveolar DPPC

2001 ◽  
Vol 280 (4) ◽  
pp. L748-L754 ◽  
Author(s):  
Aron B. Fisher ◽  
Chandra Dodia
Keyword(s):  
Degradation Products ◽  
Specific Inhibitor ◽  
Rat Lung ◽  
Lamellar Bodies ◽  
Lung Uptake ◽  
Rat Lungs ◽  
Choline Incorporation ◽  
Total Tissue ◽  
Intact Rats

This study evaluated the role of a lysosomal-type phospholipase A2(aiPLA2) in the degradation of internalized dipalmitoylphosphatidylcholine (DPPC) and in phospholipid synthesis by the rat lung. Uptake and degradation of DPPC were measured in isolated perfused rat lungs over 3 h following endotracheal instillation of [3H]DPPC in mixed unilamellar liposomes plus or minus MJ33, a specific inhibitor of lung aiPLA2. Uptake of DPPC was calculated from total tissue-associated radiolabel, and degradation was calculated from the sum of radiolabel in degradation products. Both uptake and degradation were markedly stimulated by addition of 8-bromo-cAMP to the perfusate. MJ33 had no effect on DPPC uptake but decreased DPPC degradation at 3 h by ∼40–50%. The effect of MJ33 on lung synthesis of DPPC was evaluated with intact rats over a 12- to 24-h period following intravenous injection of radiolabeled palmitate and choline. MJ33 treatment decreased palmitate incorporation into disaturated phosphatidylcholine of lamellar bodies and surfactant by ∼65% at 24 h but had no effect on choline incorporation. This result is compatible with inhibition of the deacylation/reacylation pathway for DPPC synthesis. These results obtained with intact rat lungs indicate that aiPLA2is a major enzyme for degradation of internalized DPPC and also has an important role in DPPC synthesis.

Effect of stimulation with light on synthesis and release of acetylcholine by an isolated mammalian retina

1976 ◽  
Vol 39 (6) ◽  
pp. 1210-1219 ◽  
Author(s):  
R. H. Masland ◽  
C. J. Livingstone
Keyword(s):  
Initial Rate ◽  
Horizontal Cells ◽  
High Rate ◽  
Cholinergic Synapse ◽  
Pharmacological Agents ◽  
Choline Incorporation ◽  
Rate Acceleration ◽  
Mammalian Retina ◽  
Release Of Acetylcholine ◽  
Stimulation Of

1. Acetylcholine synthesis and release were studied in rabbit retinas isolated from the eye and incubated under conditions in which their electrophysiological function is maintained. ACh synthesized from exogenous [14C] choline appeared in the retina at an initial rate of 16 nmol/g wet wt-h. Incorporation of labeled choline into ACh was accelerated by stimulation of the retina with light. 2. Retinas incubated for 40 min in the presence of labeled choline and then superfused with a medium containing an anticholinesterase released radioactive ACh into the perfusate. The rate of release increased approximately fourfold during stimulation with light. 3. When retinas were incubated with labeled choline and then superfused with medium containing no pharmacological agents, stimulation with light caused an increased release of choline into the perfusate. The recovery of labeled choline following stimulation was enhanced by hemicholinium 3. 4. Neither the light-induced release of ACh (in perfusate containing anticholinesterase) nor the light-induced release of choline (in perfusate containing no anticholinesterase) occurred if the perfusate contained 20 mM Mg2+ and 0.2 mM Ca2+. 5. Synthesis of ACh by the retina at a high rate, acceleration of choline incorporation by stimulation, and Ca2+-dependent release of ACh by stimulation are each presumptive evidence that the retina contains a cholinergic synapse. If this presumption is correct, one such synapse mayx be of an amacrine or bipolar cell since these cells can depolarize during illumination, whereas the predominant response of receptor and horizontal cells is hyperpolarization.

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