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At least 19 recordsLinked to original sources
PubMed1995

Evidence for an ethanolamine cycle: differential recycling of the ethanolamine moiety of phosphatidylethanolamine derived from phosphatidylserine and ethanolamine.

Evidence is presented for the operation of an ethanolamine-phosphatidylethanolamine (PtdEtn) cycle in Chinese hamster ovary cells. PtdEtn was labelled with [3H]ethanolamine and radioactivity was chased by incubation with 1 mM unlabelled ethanolamine. Radioactivity in [3H]PtdEtn gradually declined over a 23 h time period. In contrast, when the cells were incubated in medium lacking unlabelled ethanolamine, radioactivity in PtdEtn remained constant for at least 23 h. These observations suggest that the ethanolamine moiety is continuously released from PtdEtn and recycled back into PtdEtn. In cells incubated without unlabelled ethanolamine, labelled ethanolamine released from PtdEtn is re-incorporated into PtdEtn without significant dilution. In contrast, in cells incubated with unlabelled ethanolamine the specific radioactivity of the intracellular ethanolamine pool decreases as a result of dilution by the exogenous ethanolamine, hence radioactivity in PtdEtn gradually declines. Similar results were obtained for confluent and non-confluent cells. Our data also demonstrate that when PtdEtn is derived from phosphatidylserine decarboxylation, the ethanolamine cycle operates only in actively dividing, and not in confluent, cells, implying that PtdEtn derived from different biosynthetic origins [i.e. from decarboxylation of phosphatidylserine or from ethanolamine (most likely via the CDP-ethanolamine pathway)] is metabolized differently.

Animals↗
PubMed1998

Phosphorylation of ethanolamine, methylethanolamine, and dimethylethanolamine by overexpressed ethanolamine kinase in NIH 3T3 cells decreases the co-mitogenic effects of ethanolamines and promotes cell survival.

Ethanolamine (Etn), as well as its N-methyl (MeEtn) and N,N-dimethyl (Me2Etn) analogues, were recently shown to potentiate the stimulatory effect of insulin on DNA synthesis in serum-starved NIH 3T3 fibroblasts. In the present work we assessed the impact of the co-mitogenic effects of Etn and its methyl analogues on cell proliferation and cell survival, and examined whether the cell growth regulatory effects of these ethanolamines involve an Etn-kinase-mediated phosphorylation step. For this purpose, NIH 3T3 sublines highly overexpressing Drosophila Etn kinase and an appropriate vector control line were utilized and the effects of Etn, MeEtn, Me2Etn, methylamine (MeNH2), and dimethylamine (Me2NH) were studied. 31P-NMR analysis of the water-soluble cell metabolites revealed that both MeEtn and Me2Etn, but not choline, are excellent substrates for the expressed Etn kinase. The methylated ethanolamines (MeEtn and Me2Etn) and methylamines (MeNH2, Me2NH) were used as Etn models that can or cannot be phosphorylated, respectively. In serum-starved vector control cells, both MeNH2 (1 mM) and Me2NH (1 mM) were more effective than Etn in enhancing insulin-induced DNA synthesis, and both were almost as effective as MeEtn and Me2Etn. However, in the Etn kinase overexpressor cells the potentiating effects of Etn, MeEtn and Me2Etn, but not those of MeNH2 and Me2NH, were significantly reduced. Moreover, in the overexpressor cells, lower concentrations of Etn (50-200 microM) inhibited the combined mitogenic effects of Me2NH (1 mM) and insulin. These data are consistent with a mechanism in which the phosphorylated and non-phosphorylated ethanolamines are negative and positive regulators of insulin-induced mitogenesis, respectively. After incubating the cells for 13 days in serum-free medium in 96-well microplates, there was a steady decrease in cell numbers in both cell lines. However, between 6-13 days, 0.1-1 mM MeEtn and, particularly, Me2Etn provided significant protection against cell death in the Etn kinase overexpressor cells. In vector control cells, only Me2Etn in combination with insulin had similar effects on cell survival. The data suggest that phosphorylated ethanolamines may function as promoters of cell survival.

3T3 Cells↗
PubMed1993

The ethanolamine requirement of keratinocytes for growth is not due to defective synthesis of ethanolamine phosphoacylglycerols by the decarboxylation pathway.

We have investigated whether the growth requirement of keratinocytes for ethanolamine is due to defective synthesis of ethanolamine phosphoacylglycerols (EPG) via decarboxylation of serine phosphoacylglycerols. Proliferating keratinocytes readily incorporated [3H]ethanolamine into phosphatidylethanolamine (PE) and [3H]serine into phosphatidylserine (PS) and PE. Non-proliferating keratinocytes in ethanolamine-free medium incorporated [3H]glycerol into phosphatidylcholine (PC), PS and PE in decreasing order of label incorporated. The order of decreasing incorporation of glycerol after addition of ethanolamine to the medium was PC > PE > PS. Incubation of non-proliferating keratinocytes with [3H]serine resulted in incorporation of label into PS and PE. The extent of incorporation of [3H]serine into PS in non-proliferating keratinocytes was not less than that in proliferating cells. Addition of ethanolamine to the medium of non-proliferating keratinocytes did not change the quantity of label incorporated into PS, but resulted in a decrease of label incorporated into PE. When cells were prelabelled overnight with [3H]serine and subsequently incubated in medium containing ethanolamine, the loss of label from PS was inhibited relative to that of control cells incubated in medium without ethanolamine. The activity of PS decarboxylase activity in keratinocyte mitochondria was inhibited by phosphoethanolamine and PE, but not by ethanolamine or CDP-ethanolamine. Both proliferating and non-proliferating keratinocytes incorporated [3H]serine into ether-linked ethanolamine phospholipids. Taken together, the above results suggest that (1) both proliferating and non-proliferating keratinocytes are able to synthesize PE and ether-linked ethanolamine phospholipids from serine, and therefore the ethanolamine-requirement of the cells is not due to a defective decarboxylase pathway; (2) any inability of the decarboxylase pathway to meet cellular EPG requirement is not due to decreased synthesis of serine phospholipids; (3) synthesis of PE via decarboxylation, the major route in nonproliferating keratinocytes, appears to decrease when ethanolamine is made available and the CDP-ethanolamine pathway is functioning; (4) phosphoethanolamine and increased PE produced from the CDP-ethanolamine pathway may inhibit PS decarboxylase activity in the cells and provide a means of coordinating the synthesis of PE by the two pathways to prevent excess production.

Cell Division↗
PubMed1991

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

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.

Animals↗
PubMed2000

Differential utilization of the ethanolamine moiety of phosphatidylethanolamine derived from serine and ethanolamine during NGF-induced neuritogenesis of PC12 cells.

Neurite elongation involves the expansion of the plasma membrane and phospholipid synthesis. We investigated membrane phosphatidylethanolamine (PE) biosynthesis in PC12 cells during neurite outgrowth induced by nerve growth factor (NGF). When PE was prelabeled with [3H]ethanolamine and the radioactivity was chased by incubation with 1 mM unlabeled ethanolamine, the radioactivity of [3H]PE steadily declined and [3H]ethanolamine was released into the medium in NGF-treated cells during neurite outgrowth; in the absence of unlabeled ethanolamine, the radioactivity of [3H]PE remained relatively constant for at least 24 hr. In undifferentiated cells but not in NGF-treated cells, [3H]phosphoethanolamine accumulated in significant amounts during pulse labeling, and was converted partly to PE but largely released into the medium irrespective of incubation with unlabeled ethanolamine. The decline in the radioactivity of [3H]PE and release of [3H]ethanolamine following incubation with unlabeled ethanolamine were also observed in undifferentiated cells. Thus, the ethanolamine moiety of PE derived from ethanolamine is actively recycled in both differentiated and undifferentiated cells. When PE was derived from [3H]serine through phosphatidylserine (PS) decarboxylation, the decrease in radioactivity of [3H]PE and release of [3H]ethanolamine into the medium following incubation with unlabeled ethanolamine were observed only in NGF-treated cells, but not in undifferentiated cells, indicating that the ethanolamine moiety of PE derived from PS is actively recycled only in the cells undergoing NGF-induced neuritogenesis. Thus, in PC12 cells, the ethanolamine moiety of PE derived from PS is regulated differently from that of PE derived from ethanolamine.

Animals↗
PubMed1988

Insufficiency of transformation by simian virus 40, polyomavirus, EJ-ras, or v-myc oncogenes for conversion of ethanolamine-responsive mammary cells to ethanolamine-nonresponsive cells.

Normal mammary epithelial cells (ethanolamine responsive) require ethanolamine to enable them to grow in defined culture medium because they cannot synthesize de novo a sufficient amount of phosphatidylethanolamine. Mammary tumor cells which retain properties of the normal tissue are also likely to be ethanolamine responsive, whereas dedifferentiated, highly tumorigenic mammary tumor cells are ethanolamine nonresponsive. The nonresponsive tumor cells are able to synthesize the necessary amount of phosphatidylethanolamine to sustain growth. Therefore, the progression of malignancy seems to convert ethanolamine-responsive mammary cells to ethanolamine-nonresponsive ones. In an attempt to prove the above assumption and to understand the mechanism responsible for the conversion during the progression of malignant transformation, mammary tumor cell line 64-24, which is typically ethanolamine responsive, was transfected with simian virus 40, polyomavirus, EJ-ras, or v-myc oncogenes, and the resulting transfectants were examined for their growth response to ethanolamine. Many of the transfectants exhibited typical transformed phenotypes; however, none of the transfectants converted to ethanolamine-nonresponsive cells. Some of the SV40 and polyomavirus transformants were able to grow in the absence of ethanolamine, although they grew better in the presence of ethanolamine, unlike typical ethanolamine-nonresponsive cells. These cells could grow in the absence of ethanolamine, even though their membrane phospholipid was phosphatidylethanolamine deficient. The present study indicates that the expression of any one of the four oncogenes tested, which allows the cells to exhibit transformed phenotypes in 64-24 cells, is not sufficient for the conversion of ethanolamine-responsive cells to -nonresponsive cells.

Animals↗
PubMed1985

The utilization of ethanolamine and serine for ethanolamine phosphoglyceride synthesis by human Y79 retinoblastoma cells.

Phospholipid synthesis was investigated in human Y79 retinoblastoma cells, a cultured cell line of retinal origin that retains many neural characteristics. Ethanolamine is taken up by Y79 cells through a high-affinity transport system and is utilized to synthesize ethanolamine and choline phosphoglycerides. High-affinity ethanolamine uptake has a K'm of 40.6 microM and a V'max of 1.06 nmol/min/mg protein, and the process is Na+ dependent. Choline is the only compound tested that reduced ethanolamine uptake, and very high choline concentrations were required to produce this effect. The cells incorporate ethanolamine into phosphatidylethanolamine and ethanolamine plasmalogen at equivalent rates, and the rates of catabolism of these phospholipids are similar. Only a small quantity of ethanolamine is incorporated into phosphatidylcholine, but the amount is not reduced by the addition of choline. Serine is incorporated into phosphatidylserine, which then is converted to phosphatidylethanolamine. Ethanolamine reduces but does not abolish this conversion. Unlike ethanolamine, only a small amount of serine is incorporated into ethanolamine plasmalogen. It is possible that the ethanolamine high-affinity uptake system is necessary to provide a neural cell with enough free ethanolamine for ethanolamine plasmalogen synthesis.

Cell Line↗
PubMed2000

Overexpression of a mammalian ethanolamine-specific kinase accelerates the CDP-ethanolamine pathway.

Ethanolamine kinase (EKI) is the first committed step in phosphatidylethanolamine (PtdEtn) biosynthesis via the CDP-ethanolamine pathway. We identify a human cDNA encoding an ethanolamine-specific kinase EKI1 and the structure of the EKI1 gene located on chromosome 12. EKI1 overexpression in COS-7 cells results in a 170-fold increase in ethanolamine kinase-specific activity and accelerates the rate of [3H]ethanolamine incorporation into PtdEtn as a function of the ethanolamine concentration in the culture medium. Acceleration of the CDP-ethanolamine pathway does not result in elevated cellular PtdEtn levels, but rather the excess PtdEtn is degraded to glycerophosphoethanolamine. EKI1 has negligible choline kinase activity in vitro and does not influence phosphatidylcholine biosynthesis. Acceleration of the CDP-ethanolamine pathway also does not change the rate of PtdEtn formation via the decarboxylation of phosphatidylserine. The data demonstrate the existence of separate ethanolamine and choline kinases in mammals and show that ethanolamine kinase can be a rate-controlling step in PtdEtn biosynthesis.

Amino Acid Sequence↗
PubMed1975

Mechanism of action of ethanolamine ammonia-lyase, an adenosylcobalamin-dependent enzyme. Proton nuclear magnetic resonance studies of the binding of adenine nucleosides and substrate to ethanolamine ammonia-lyase.

Proton NMR spectroscopy was used to study the binding of adenosine, 5'-deoxyadenosine, adenine, and ethanolamine to the adenosylcobalamin-dependent enzyme ethanolamine ammonia-lyase. Broadening of ligand resonances in the presence of ethanolamine ammonia-lyase indicated that adenosine, 5'-deoxyadenosine, and ethanolamine all formed complexes with the enzyme (KD(mM) = 3.5, 3.0, and 2.5 respectively). The methyl group of enzyme-bound 5'-deoxyadenosine rotated at a rate exceeding 10(7) revolutions/s. Adenine did not appear to bind to the enzyme. Rates of dissociation of nucleosides from the enzyme were fast on the NMR time scale, precluding measurements of rate constants for the binding reaction. The departure of ethanolamine was slow, however, permitting their determination. The values for these rate constants were: k1 = 4.4 times 10(5) M-1 S-1; k-1 = 1.1 times 10(3) S-1. Addition of 1 mol of cyanocobalamin/mol of active sites led to narrowing of the enzyme-broadened ligand resonances. With 5'-deoxyadenosine, linewidths still exceeded those of the free ligand, indicating that binding to enzyme was weakened but not abolished. The KD for this nucleoside in the presence of CNCbl was 8.0 mM. With ethanolamine and adenosine, however, linewidths reverted to values characteristic of the unbound ligand, indicating either that CNCbl greatly lowered the rate of dissociation of the ligand or displaced the ligand from the enzyme. A decision between these two possibilities could not be made from the data at hand, although analogy with the situation obtaining with 5'-deoxyadenosine suggests that adenosine is displaced from the enzyme by CNCbl. 5'-Deoxyadenosine inhibited catalytic activity of the enzyme, competing with adenosylcobalamin (Ki = 2.7 mM). Adenosine had no effect, despite NMR evidence indicating that it formed a complex with free enzyme. These experiments showed that ethanolamine ammonia-lyase possesses binding sites for adenine nucleosides, a class of compounds chemically related to the Cobeta-ligand of the cofactor, as well as for ethanolamine. Binding to the enzyme has now been demonstrated for all three categories of low molecular weight compounds thought to be involved in the reaction; namely, substrate (ethanolamine), corrin, and adenine nucleoside.

Adenine↗
PubMed1979

Influence of choline and ethanolamine administration on choline and ethanolamine phosphorylating activities of mouse liver and kidney.

The administration of ethanolamine to adult male mice resulted in a significant increase in ethanolamine kinase activity in liver and kidney. Similarly, choline administration resulted in a significant increase in choline kinase activity in liver and kidney. The administration of ethanolamine resulted in enhancement of choline kinase activity concomitantly with ethanolamine kinase activity in liver and kidney. The administration of choline, however, did not result in any significant increase in ethanolamine kinase activity in liver or kidney. Cycloheximide administration along with choline-ethanolamine prevented the increase in kinase activity in liver and kidney. The results obtained have been discussed in relation to the regulatory role of choline kinase and ethanolamine kinase by de novo synthesis in response to enhanced substrate concentration, the secondary nature of choline kinase induction on ethanolamine administration, and possible distinction between choline kinase and ethanolamine kinase.

Animals↗
PubMed1994

Functional redundancy of CDP-ethanolamine and CDP-choline pathway enzymes in phospholipid biosynthesis: ethanolamine-dependent effects on steady-state membrane phospholipid composition in Saccharomyces cerevisiae.

It has been established that yeast membrane phospholipid content is responsive to the inositol and choline content of the growth medium. Alterations in the levels of transcription of phospholipid biosynthetic enzymes contribute significantly to this response. We now describe conditions under which ethanolamine can exert significant influence on yeast membrane phospholipid composition. We demonstrate that mutations which block a defined subset of the reactions required for the biosynthesis of phosphatidylcholine (PC) via the CDP-choline pathway cause ethanolamine-dependent effects on the steady-state levels of bulk PC in yeast membranes. Such an ethanolamine-dependent reduction in bulk membrane PC content was observed for both choline kinase (cki) and choline phosphotransferase (cpt1) mutants, but it was not observed for mutants defective in cholinephosphate cytidylyltransferase, the enzyme that catalyzes the penultimate reaction of the CDP-choline pathway for PC biosynthesis. Moreover, the ethanolamine effect observed for cki and cpt1 mutants was independent of the choline content of the growth medium. Finally, we found that haploid yeast strains defective in the activity of both the choline and ethanolamine phosphotransferases experienced an ethanolamine-insensitive reduction in steady-state PC content, an effect which was not observed in strains defective in either one of these activities alone. The collective data indicate that specific enzymes of the CDP-ethanolamine pathway for phosphatidylethanolamine biosynthesis, while able to contribute to PC synthesis when yeast cells are grown under conditions of ethanolamine deprivation, do not do so when yeast cells are presented with this phospholipid headgroup precursor.

Carrier Proteins↗
PubMed1997

Extracellular sphingosine 1-phosphate stimulates formation of ethanolamine from phosphatidylethanolamine: modulation of sphingosine 1-phosphate-induced mitogenesis by ethanolamine.

In this work, we determined the effects of sphingosine 1-phosphate (S1P) on phospholipase D (PLD)-mediated hydrolysis of phosphatidylethanolamine (PtdEtn), and evaluated the effects of the water-soluble product ethanolamine on S1P-induced DNA synthesis in NIH 3T3 cells. In [14C]ethanolamine-labelled cells, S1P (0.5-5 microM) stimulated PLD-mediated hydrolysis of PtdEtn 1.5-2.1-fold. Down-regulation of protein kinase C by chronic (24 h) treatment of cells with 300 nM PMA, or pretreatments (10 min) with the cell-permeant calcium chelator 1,2-bis-(O-aminophenoxy)-ethane-N,N, N',N'-tetra-acetic acid tetra-acetoxymethyl ester led to the inhibition of S1P-induced PtdEtn hydrolysis. S1P alone was a weak inducer of DNA synthesis, but its effects were enhanced by phosphocholine (PCho), insulin, ATP or PMA. Ethanolamine (5-100 microM) did not modify the mitogenic effect of S1P alone, whereas at 50-100 microM concentrations it actually enhanced the mitogenic effect of PCho via a mitogen-activated protein (MAP) kinase-independent mechanism. In contrast, 5-20 microM concentrations of ethanolamine, which correspond to normal blood ethanolamine levels in humans, strongly inhibited DNA synthesis induced by S1P plus PCho via a MAP kinase-dependent mechanism; importantly, less or no inhibition was observed with 50-100 microM concentrations of ethanolamine. At 5-50 microM concentrations, ethanolamine also inhibited the synergistic mitogenic effects of both S1P plus insulin (22-27% inhibition) and PCho plus ATP (45-73% inhibition) but not those of S1P plus PMA or S1P plus ATP. The results indicate that S1P stimulates PLD-mediated hydrolysis of PtdEtn by a mechanism that may involve a regulatory protein kinase C isoform. Increased formation of ethanolamine by PLD-mediated PtdEtn hydrolysis or by other means may be required for maximal stimulation of DNA synthesis by S1P in the presence of insulin, and particularly PCho.

3T3 Cells↗
PubMed1989

Murine elongation factor 1 alpha (EF-1 alpha) is posttranslationally modified by novel amide-linked ethanolamine-phosphoglycerol moieties. Addition of ethanolamine-phosphoglycerol to specific glutamic acid residues on EF-1 alpha.

Elongation Factor 1 alpha (EF-1 alpha), an important eukaryotic translation factor, transports charged aminoacyl-tRNA from the cytosol to the ribosomes during poly-peptide synthesis. Metabolic radiolabeling with [3H] ethanolamine shows that, in all cells examined, EF-1 alpha is the major radiolabeled protein. Radiolabeled EF-1 alpha has an apparent Mr = 53,000 and a basic isoelectric point. It is cytosolic and does not contain N-linked oligosaccharides. Trypsin digestion of murine EF-1 alpha generated two major [3H]ethanolamine-labeled peptides. Three peptides were sequenced and were identical to two distinct regions of the human EF-1 alpha protein. Blank sequencing cycles coinciding with glutamic acid in the human cDNA-derived sequence were also found to release [3H]ethanolamine, and compositional analysis of these peptides confirmed the presence of glutamic acid. Dansylation analysis demonstrates that the amine group of the ethanolamine is blocked. These results indicate that EF-1 alpha is posttranslationally modified by the covalent attachment of ethanolamine via an amide bond to at least two specific glutamic acid residues (Glu-301 and Glu-374). The hydroxyl group of the attached ethanolamine was shown by mass spectrometry and compositional analysis, to be further modified by the addition of a phosphoglycerol unit. This novel posttranslational modification may represent an important alteration of EF-1 alpha, comparable to the regulatory effects of posttranslational methylation of EF-1 alpha lysine residues.

Amino Acid Sequence↗
PubMed1975

Regulation of phospholipid metabolism in differentiating cells from rat brain cerebral hemipheres in culture. II. Incorporation of [U-14C]ethanolamine into 1-alkenyl,2-acyl-and 1,2 diacyl-ethanolamine phosphoglycerides.

Cultured dissociated cells from rat embryo cerebral hemisphere incorporate [3H]-and [U-14C]ethanolamine into cellular lipids. Nearly all radioactivity in the lipid fractions is incorporated into 1,2-diacylethanolamine phosphoglycerides and 1-alkenyl,2-acylethanolamine phosphoglycerides (plasmalogen). Kinetic data suggest that the rate of labeling of both ethanolamine phospholipids from the phosphorylethanolamine is similar. A relative increase of the plasmalogen labeling is observed when free ethanolamine is continually present in the medium. The rate of incorporation of label from ethanolamine and phosphorylethanolamine into lipids was measured using a double label technique. Based upon these studies, an independent labeling pattern of the ethanolamine moiety of plasmalogens is suggested. A relative delay for the incorporation of label in plasmalogens could be explained by the presence of a variety of cell types which may differ in their capacity for phospholipid biosynthesis. The rate of incorporation of phosphorylethanolamine into the phosphatidylethanolamine was not affected by the presence of high concentrations of either choline or serine.

Animals↗
PubMed1992

Comparative effects of 5% ethanolamine oleate versus 5% ethanolamine oleate plus 1% polidocanol for sclerosing esophageal varices.

Sixty-six patients with portal hypertension and esophageal varices due to liver cirrhosis were randomized to receive either 5% ethanolamine oleate (EO) or 5% EO plus 1% polidocanol (EOP) as a sclerosant for endoscopic injection sclerotherapy (EIS). The two groups were well matched with regard to age, sex and the severity of liver disease. In no patient in the two groups was there any major complication, such as esophageal perforation or esophageal bleeding. Eradication of esophageal varices was attained with an average of 4.7 and 4.3 sessions of endoscopic injection sclerotherapy in the ethanolamine oleate and polidocanol groups, respectively. Data on one patient in the ethanolamine oleate group had to be excluded because he left the hospital after 2 sessions of endoscopic injection sclerotherapy. Esophageal ulcers occurred earlier in the polidocanol group (after an average of 2.8 weeks) than in the ethanolamine oleate group (3.8 weeks), the difference being statistically significant (P < 0.01). The rate of occurrence of esophageal stricture requiring more than 2 sessions of bougienage was significantly (P < 0.01) higher in the polidocanol group (16/33, 48%) than in the ethanolamine oleate group (4/32, 12%). This study suggests that the two sclerosants have equal efficacy for treating patients with esophageal varices. With polidocanol there was ulceration and stricture in the distal esophagus.

Drug Combinations↗
PubMed1982

Interaction of N-substituted ethanolamine analogs with ethanolamine ammonia-lyase, an adenosylcobalamin-requiring enzyme.

A number of N-substituted ethanolamine derivatives have been found to interact productively with ethanolamine ammonia-lyase, an adenosylcobalamin (AdoCbl) requiring enzyme that catalyzes the conversion of vicinal amino alcohols to oxo compounds. Inhibition, inactivation, cleavage of AdoCbl, and exchange of tritium out of [5'-3H]AdoCbl were all observed, the effects varying from analog to analog. The most striking effects were seen with azetidin-2-ol and pyrrolidin-3-ol, two aliphatic heterocycles composed of ethanolamine in which the nitrogen is tied back to the carbinol carbon by methylene bridges containing one and two carbon atoms, respectively. Incubation of azetidinol with the enzyme.AdoCbl complex resulted in extensive inactivation of the enzyme accompanied by cleavage of the cofactor; exchange of 3H from [5'-3H]AdoCbl into a nonbasic compound was also seen. Pyrrolidinol interacted with the enzyme.AdoCbl complex in a substrate-like way, causing exchange of 3H from labeled cofactor into a basic compound (perhaps the pyrrolidinol itself) together with a slight amount of C-Co bond cleavage. The interaction of the enzyme.AdoCbl complex with pyrrolidinol suggests that productively bound substrate is associated with the active site in such a way that the dihedral angle between the nitrogen and the oxygen is about 120 degrees, a configuration which maximizes bond-bond repulsions between the substituents on the adjacent carbon atoms.

Ammonia-Lyases↗
PubMed1989

2-Aminoethylarsonic acid as an analogue of ethanolamine phosphate. Endowment of ethanolamine-phosphate cytidylyltransferase with CTP pyrophosphatase activity.

2-Aminoethylarsonic acid was tested for its ability to act as a substrate for ethanolamine-phosphate cytidylytransferase as a cytidylyl acceptor in place of ethanolamine phosphate. The expected product, like all mixed anhydrides of arsonic acids, should hydrolyse spontaneously with regeneration of the substrate analogue and CMP formation; such CMP production was observed. The limiting velocity with aminoethylarsonic acid is about 90% that with ethanolamine phosphate, and the Michaelis constant is below 20 mM.

Arsenicals↗