Effect of mitochondrial inhibitors on [3H]choline incorporation into choline metabolites in cholinergic LA-N-2 cells

2000 ◽  
Vol 21 ◽  
pp. 183
Author(s):  
Amandip K. Utal ◽  
Paul D. Coleman
Keyword(s):  
Mitochondrial Inhibitors ◽  
Choline Incorporation

Regulation of cytosolic free Ca2+ concentration in acinar cells of rat pancreas

1983 ◽  
Vol 245 (3) ◽  
pp. G347-G357 ◽  
Author(s):  
H. Streb ◽  
I. Schulz
Keyword(s):  
Steady State ◽  
Incubation Medium ◽  
Minimal Medium ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Atpase Inhibitor ◽  
Rat Pancreas ◽  
Mitochondrial Inhibitors ◽  
Pancreatic Cells ◽  
State Concentration

Ca2+ uptake into isolated exocrine pancreatic cells with highly permeable plasma membrane was determined by measuring the decrease in free Ca2+ concentration of the surrounding incubation medium with a Ca2+-specific electrode. In the presence of Mg-ATP and respiratory substrates the free Ca2+ concentration of the incubation medium decreased rapidly after addition of leaky cells until a stable medium free Ca2+ concentration of 4.2 +/- 0.1 X 10(-7) mol/l was obtained. Changes in the medium free Ca2+ concentration at steady state by addition of Ca2+ or EGTA were buffered by cellular uptake or release, respectively, until the steady-state free Ca2+ concentration was reestablished. When nonmitochondrial Ca2+ uptake was determined in the presence of a combination of mitochondrial inhibitors (10(-5) mol/l antimycin, 5 X 10(-6) mol/l oligomycin, and 10(-2) mol/l azide), the rate of uptake was considerably reduced, while the steady-state concentration was unaltered. In contrast, mitochondrial uptake that could be observed in the presence of the ATPase inhibitor vanadate (2 X 10(-3) mol/l) proceeded at the same rate as the control, but the minimal medium free Ca2+ concentration reached was 2.4 +/- 0.1 X 10(-7) mol/l higher than the control. Addition of secretagogues at steady-state free Ca2+ concentration resulted in a Ca2+ release of 0.73 +/- 0.08 nmol/mg protein. The increase in medium free Ca2+ concentration was entirely transient and followed by reuptake to the prestimulation level. The data indicate that a cytosolic free Ca2+ concentration of 4 X 10(-7) mol/l can be regulated in pancreatic acinar cells by a nonmitochondrial Mg2+-dependent Ca2+ pool.

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.

Differential effects of mitochondrial inhibitors on porcine granulosa cells and oocytes

2017 ◽  
Vol 103 ◽  
pp. 98-103 ◽  
Author(s):  
Kazuki Kansaku ◽  
Nobuhiko Itami ◽  
Ryouka Kawahara-Miki ◽  
Koumei Shirasuna ◽  
Takehito Kuwayama ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Differential Effects ◽  
Mitochondrial Inhibitors ◽  
Porcine Granulosa Cells

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

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