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At least 19 recordsLinked to original sources
PubMed1972

Glycerylphosphorylcholine phosphodiesterase in rat liver. Subcellular distribution and localization in plasma membranes.

1. A simple new assay for glycerylphosphorylcholine phosphodiesterase is described, in which radioactive glycerylphosphorylcholine is used as substrate and the reaction products are separated by adsorption on an anion-exchange resin. 2. Rat liver subcellular fractions contained both particulate (58%) and soluble (42%) glycerylphosphorylcholine phosphodiesterase. Both activities released free choline from glycerylphosphorylcholine. 3. The particulate glycerylphosphorylcholine phosphodiesterase was recovered mainly in the nuclear and microsomal fractions and showed a distribution similar to those of 5'-nucleotidase and alkaline phosphodiesterase I, both of which are constituents of the liver plasma membrane. 4. During purification of plasma membranes glycerylphosphorylcholine phosphodiesterase, 5'-nucleotidase and alkaline phosphodiesterase I showed largely similar behaviour, indicating that glycerylphosphorylcholine phosphodiesterase is also localized in liver plasma membranes. Slight differences in the distributions of these three enzymes in density-gradient separations are discussed in relation to the possibility that they are unevenly distributed on different areas of the cell surface. 5. The differences between glycerylphosphorylcholine phosphodiesterase and alkaline phosphodiesterase I indicate that these two activities are not functions of a single enzyme. 6. The glycerylphosphorylcholine phosphodiesterase of liver plasma membranes has a pH optimum of 8.5 and a K(m) for glycerylphosphorylcholine of 0.95mm. It is inhibited by EDTA and fully reactivated by a variety of bivalent cations (and Fe(3+)).

Animals↗
PubMed1971

Mass spectrometry of the phosphatidylcholines: dipalmitoyl, dioleoyl, and stearoyl-oleoyl glycerylphosphorylcholines.

Mass spectra of the diacyl glycerylphosphorylcholines have been obtained using a direct insertion probe, with a source temperature of 250 degrees C at an ionizing potential of 70 ev. Fragmentation patterns are described for dipalmitoyl, dioleoyl, and 1-stearoyl-2-oleoyl glycerylphosphorylcholines. Significant differences are observed in the fragmentation patterns, and the fragment ions have been identified by high resolution mass measurements. Ions associated with the hydrocarbon chains, glycerol esters, and phosphorylcholine have been identified, and the presence of metastable transitions have been used as confirmatory evidence for some of the steps involved in the fragmentation sequence. A molecular ion was tentatively identified in the case of dioleoyl glycerylphosphorylcholine. The mass spectrum of 1-stearoyl-2-oleoyl glycerylphosphorylcholine shows an important rearrangement ion at m/e 604 and some evidence for the differential cleavage, or stability, of the stearoyl- and oleoyl-containing fragments. Strong similarities exist between the observed spectra for the diacyl glycerylphosphorylcholines and those for the corresponding glycerides.

Chemical Phenomena↗
PubMed1987

Simultaneous measurement of seminal L-carnitine, alpha,1-4-glucosidase, and glycerylphosphorylcholine in azoospermic and oligozoospermic patients.

L-carnitine, alpha,1-4-glucosidase, and glycerylphosphorylcholine were measured in seminal plasma of a selected group of azoospermic men and in an unselected group of oligozoospermic men. In vasectomized subjects the epididymal indices (mean +/- standard error: L-carnitine, 276.9 +/- 27.5 nmol/ejaculate; alpha-glucosidase, 1.2 +/- 0.1 U/ejaculate; and glycerylphosphorylcholine, 1.5 +/- 0.2 mumol/ejaculate) were always below the normal range of fertile subjects (1757.4 +/- 76.7 nmol/ejaculate; 16.4 +/- 0.9 U/ejaculate; and 17.3 +/- 0.7 mumol/ejaculate, respectively). On the contrary in a large number of patients affected by azoospermia because of seminiferous tubular damage (750.4 +/- 83.6 nmol/ejaculate; 6.8 +/- 0.9 U/ejaculate; and 6.1 +/- 0.6 mumol/ejaculate; respectively) and in a few oligozoospermic subjects (1193.7 +/- 72.3 nmol/ejaculate; 10.3 +/- 0.7 U/ejaculate; and 10.8 +/- 0.7 mumol/ejaculate; respectively) the epididymal indices were found in the range of vasectomized subjects, showing an association between seminiferous tubular lesion and epididymal dysfunction. In conclusion, in spite of the low levels of epididymal indices found in patients with obstructive azoospermia, the presence of a large number of subjects with seminiferous tubular lesions without obstruction with similar low values of L-carnitine, alpha-glucosidase, and glycerylphosphorylcholine reduces the usefulness of these indices in differential diagnosis of azoospermia.

Carnitine↗
PubMed1971

Mass spectrometry of the phosphatidylcholines: fragmentation processes for dioleoyl and stearoyl-oleoyl glycerylphosphorylcholine.

Mass spectra for the various phosphatidylcholines, together with accurate mass measurements on the more abundant fragment ions, have been described in a previous paper (Ref. 5). No detailed fragmentation sequence was proposed on the evidence available. In the case of dioleoyl glycerylphosphorylcholine, some question arose as to whether certain ions were produced by electron impact or by pyrolysis. In this paper, results are reported which enable a more detailed fragmentation sequence to be proposed. By observing metastable transitions in the first field free region of a double-focusing mass spectrometer, it can be shown that the major ions in the spectrum are produced by electron impact processes, and not by pyrolysis; moreover, many of these ions are directly related to one another by metastable processes. In particular, it has been demonstrated that the ions at m/e 603 for dioleoyl glycerylphosphorylcholine and at m/e 604 for stearoyl-oleoyl glycerylphosphorylcholine are derived from the appropriate molecular ions by an electron impact-induced process. From measurements of the metastable ion intensities, as well as from the appearance potentials and ionization efficiency curves, conclusions may be drawn about many of the fragmentation mechanisms, allowing a distinction to be made between rearrangement and cleavage reactions.

Chemical Phenomena↗
PubMed1981

Isolation of epithelial cells from the corpus epididymidis and analysis for glycerylphosphorylcholine, sialic acid, and protein.

Enzymatically dispersed cells from the rat corpus epididymidis were separated by unit gravity sedimentation and centrifugal elutriation. Based on differential cell counts, principal cells isolated by centrifugal elutriation were 55% pure, while basal cells and fibroblasts were 88% and 61% pure, respectively. Compared to unit gravity separation, purity was an average of 7% higher in principal and basal cell fractions obtained by elutriation. Viability was greater than 87% by either method, but yields following elutriation averaged 23% higher for basal cells, 78% higher for principal cells, and 290% for fibroblasts than corresponding yields following unit gravity separation. Analyses for epididymal secretory products indicated that cellular content (mumoles/10(9) cells) of glycerylphosphorylcholine (GPC), sialic acid, and protein was greater in principal cells than other cell types (p less than .05). When expressed on the basis of cellular volume, concentrations of GPC and protein also were significantly greater in basal and principal cells than fibroblasts (p less than .05). Caput sperm contained significantly more GPC than either corpus or cauda sperm (p less than .005). Protein concentrations in caput and corpus sperm were similar, but concentrations were lower in cauda sperm (p less than .005). Levels of sialic acid did not vary among sperm from different epididymal regions. It was concluded that principal cells from the corpus epididymidis contain major quantities of three epididymal secretory products and that regional differences in the function of the epithelium are present.

Animals↗
PubMed1994

Ca2+ dependent activation of rat uterine glycerylphosphorylcholine diesterase: presence of a positive modulator protein in uterine secretion.

The rat uterine secretory enzyme glycerylphosphorylcholine (GPC) diesterase (EC 3.1.4.2) had been purified and characterized previously with respect to its mol. wt., size, amino acid, carbohydrate composition and estrogen inducible properties. This enzyme is observed to have exclusive specificity for GPC and exhibits characteristic hyperbolic kinetics with Ca2+ in an ethyleneglycolbis N'N'N'N' tetraacetic acid (EGTA) buffered system. Ca2+ reduces Km of the enzyme for GPC from 0.65 to 0.25 mM. The Km for GPC of the partially purified enzyme is found to be 0.35 mM without addition of calcium which indicates the presence of a positive modulator of the enzyme in this fraction. Based on this rationale, a protein activating factor for the enzyme was isolated from this fraction which has a native size of 18 KD as observed on Sephacryl S-200 chromatography and strikingly stimulates enzyme activity at around 0.55 microM.

Animals↗
PubMed1996

Evidence for an in vivo and in vitro modulation of endogenous cortical GABA release by alpha-glycerylphosphorylcholine.

The effects of alpha-glycerylphosphorylcholine (alpha-GPC) on endogenous cortical GABA release were studied both in vivo and in vitro. In freely moving rats, equipped with epidural cups, alpha-GPC (30-300 mg/kg i.p.) increased GABA release. This effect was potentiated by atropine, both systematically administered (5 mg/kg i.p.) and locally applied (1.4 microM), but not by mecamylamine (4 mg/kg i.p.). The alpha-GPC-induced increase in GABA release was abolished in rats pretreated with the alpha 1 receptor antagonist prazosin (14 micrograms/kg i.p.). In cortical slices alpha-GPC (0.4 mM) increased the spontaneous GABA efflux. This effect was abolished by tetrodotoxin (0.5 microM) and prazosin (1 microM), but not by atropine (0.15 microM) or mecamylamine (2.5 microM). These results indicate that the facilitatory response by alpha-GPC on GABA release does not depend on a direct activation of either muscarinic or nicotinic receptors, but suggest the involvement of the noradrenergic system.

Animals↗
PubMed1992

L-alpha-glycerylphosphorylcholine antagonizes scopolamine-induced amnesia and enhances hippocampal cholinergic transmission in the rat.

The effects of L-alpha-glycerylphosphorylcholine (alpha-GPC) on scopolamine-induced memory impairment and on brain acetylcholine (ACh) synthesis and release were investigated in rats. Oral administration of alpha-GPC 3 h before the behavioural test prevented the learning impairment induced by scopolamine given 30 min before the acquisition of a passive avoidance response. Similarly, retrograde amnesia induced by scopolamine, given immediately after acquisition training, was also completely reversed by the drug. These effects were dose-dependent with a maximum at 300 mg/kg. The mechanism of action of this compound was investigated by measuring hippocampal ACh synthesis and release both in vivo by means of the microdialysis technique and in vitro in tissue slices. alpha-GPC dose dependently increased ACh release with a maximum at 300 mg/kg. In addition, i.v. injection of [14C]alpha-GPC resulted in [14C]ACh formation. The data suggest that the behavioural effects of alpha-GPC may be related to its property to increase hippocampal ACh synthesis and release.

Acetylcholine↗
PubMed1992

Behavioral effects of L-alpha-glycerylphosphorylcholine: influence on cognitive mechanisms in the rat.

The phosphorylcholine precursor, L-alpha-glycerylphosphorylcholine (alpha-GPC), was injected at the dose of 100 mg/kg/day for 20 days to aged male rats of the Sprague-Dawley strain, 24 months old, showing a deficit of learning and memory capacity. The drug was also administered to rats with amnesia induced pharmacologically with bilateral injections of kainic acid into the nucleus basalis magnocellularis (NBM). Learning and memory capacity of the animals, studied with tests of active and passive avoidance behavior, was improved after treatment with alpha-GPC in all experimental groups. These results indicate that this drug affects cognitive mechanisms in the rat through an involvement of central neurotransmission.

Animals↗
PubMed1992

Molecular mechanisms mediating the effects of L-alpha-glycerylphosphorylcholine, a new cognition-enhancing drug, on behavioral and biochemical parameters in young and aged rats.

The behavioral effects of the acute and subchronic administration of L-alpha-glycerylphosphorylcholine (alpha-GPC) on passive and active avoidance behavioral tasks were investigated. When administered IP after training together with scopolamine 2 h before retest, alpha-GPC reverses the scopolamine-induced amnesia in the passive avoidance conditioning in young and old rats. Furthermore, the subchronic treatment with alpha-GPC positively and significantly influences the performance of both young and old animals in the active avoidance test. Moreover, in in vitro/ex vivo experiments alpha-GPC potentiates receptor-stimulated phosphatidylinositol hydrolysis in cortical synaptoneurosomes derived from young and old animals. In young but not old animals, alpha-GPC significantly potentiates potassium (40 mM)-stimulated intrasynaptosomal calcium oscillations in purified synaptosomes derived from the hippocampus. These results show that alpha-GPC improves the performance of animals in both active and passive conditioning tasks. Furthermore, subchronic treatment with the compound enhances in young and restores in aged animals the transduction of the signal, namely, the receptor-mediated production of inositol phosphate and the potassium-induced calcium mobilization. These modifications may represent at least part of the molecular mechanism of action of the compound.

Adenylyl Cyclases↗
PubMed1996

Effect of L-alpha glycerylphosphorylcholine on muscarinic receptors and membrane microviscosity of aged rat brain.

1. Old rats showed a significant decrease in the number of muscarinic M(1) receptors and a significant increase in membrane microviscosity in the striatum and hippocampus as compared to young animals. In contrast, no significant changes in the density of muscarinic M(2) receptors were observed with aging. 2. Chronic treatment of aged rats with L-alpha-glycerylphosphorylcholine (L-alpha-GPC) restored the number of M(1) receptors to levels found in the striatum and hippocampus from young animals. The same treatment to aged rats partially restored membrane microviscosity in both regions studied and hence increased membrane fluidity. 3. None of the major metabolites of L-alpha-GPC (choline, glycerophosphate or phosphorylcholine) was able to restore the number of striatal and hippocampal M(1) sites and membrane microviscosity of aged rats, neither did any of these treatments (including treatment with L-alpha-GPC) modify the level of M(1) receptors and microviscosity values in young rats.

Aging↗
PubMed1991

A highly sensitive chemiluminescent assay for glycerylphosphorylcholine in human seminal plasma.

Glycerylphosphorylcholine (GPC), one of the major phosphorus-containing-choline compounds of seminal plasma, is secreted mainly by the epididymal epithelium under androgenic control. This study reports a new method that uses chemiluminescence to determine seminal GPC content, comparing it with a spectrophotometric technique. The results, obtained with both techniques studying 20 fertile patients (as control), 35 infertile patients with normospermia, 23 infertile patients with oligozoospermia and impaired motility and 9 patients with excretory azoospermia, demonstrate that the GPC chemiluminescent assay is more sensitive, simple and rapid than the spectrophotometric assay. Our data confirm that GPC may be used as a marker of vas deferens and ejaculatory duct perviousness, suggesting a possible role of this glycerophosphodiester in sperm motility.

Glycerylphosphorylcholine↗
PubMed1979

Seminal plasma concentration of glycerylphosphorylcholine before and after vasectomy and vas reanastomosis.

The concentration of glycerylphosphorylcholine (GPC) was determined in semen obtained from normal fertile, vasectomized, and vas-reanastomosed subjects. Concentrations of GPC were markedly lower in the semen of vasectomized men. GPC levels observed in vas-reanastomosed subjects were similar to those found in normal fertile men. Vasectomy may not affect GPC synthesis significantly.

Glycerylphosphorylcholine↗
PubMed1994

Association of glycerylphosphorylcholine with human sperm and effect of capacitation on their metabolism.

The presence and localization of glycerylphosphorylcholine (GPC) on the surface of human sperm, as well as the metabolism of its breakdown product L-glycerol 3 phosphate (G3P), were investigated. GPC was found to be associated with sperm after penetrating cervical mucus and was present after repeated washing of the sperm. GPC was partially released by treatment with 0.4 M NaCl in 0.01 M sodium phosphate buffer (pH 7.4) and localized to the head region after sperm fractionation. G3P did not increase O2 uptake of uncapacitated human sperm. However, under aerobic conditions, lactate accumulated when exogenous G3P or uterine GPC diesterase was added to sperm in suspension. The uptake of O2 by washed capacitated sperm pre-incubated with 1 unit of rat uterine GPC diesterase for 30 min was significant. This effect was inhibited by 2 microM oligomycin indicating that oxidative phosphorylation had occurred. The present study indicates that GPC may play a role in the metabolism of human sperm after capacitation.

Glycerophosphates↗
PubMed1993

PKC translocation in rat brain cortex is promoted in vivo and in vitro by alpha-glycerylphosphorylcholine, a cognition-enhancing drug.

Protein kinase C (PKC) activity was measured in soluble and particulate fractions of rat individual brain areas after treatment with alpha-glycerylphosphorylcholine (GPC), a cognition-enhancing drug which promotes acetylcholine synthesis and release. The drug induced both in vivo and in vitro PKC translocation. In vivo, an increase of particulate PKC activity was observed 1 hour following the acute oral administration of a behaviorally active dose (600 mg/kg); the effect was transient. In vitro, GPC promoted PKC translocation in cortical slices at concentrations as low as 50 nM; the concentration-response curve was bell shaped. The increased PKC activity may be related to the cortical effects of GPC.

Amphetamine↗
PubMed1993

Cholinergic neurotransmission in the hippocampus of aged rats: influence of L-alpha-glycerylphosphorylcholine treatment.

The influence of aging and of L-alpha-glycerylphosphorylcholine (GFC) treatment on the acetylcholine synthesizing and degradating enzymes choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) and on cholinergic muscarinic M-1 and M-2 receptors were assessed in the hippocampus using immunocytochemical, histochemical and radioligand binding techniques, respectively. The investigation was performed on male Wistar rats of 2 months (young), 12 months (adult), and 27 months (old). Oral GFC was given at the dose of 100 mg/Kg/day from the 21st to the 27th month of age. ChAT revealed the highest immunostaining in the hippocampus of adult rats followed by young and old animals. The highest expression of AChE reactivity was noticeable in the hippocampus of adult rats followed by old and young animals. Treatment with GFC restored in part ChAT immunoreactivity and AChE reactivity in the hippocampus of aged rats. Muscarinic M-1 and M-2 receptors were labeled with [3H]-pirenzepine and [3H]-AF-DX-116 respectively. The density of M-1 muscarinic receptors decreased with age, whereas M-2 muscarinic receptors did not change. GFC treatment countered in part the loss of M-1 receptors in old rats and was without effect on M-2 receptors.

Acetylcholine↗
PubMedDate not supplied

A multicentre trial to evaluate the efficacy and tolerability of alpha-glycerylphosphorylcholine versus cytosine diphosphocholine in patients with vascular dementia.

An open clinical trial was carried out to compare the efficacy and the tolerability of 1 g/day alpha-glycerylphosphorylcholine (alpha-GPC) with 1 g/day cytosine diphosphocholine (CDP) both given intramuscularly for 90 days in 120 patients with mild to moderate vascular dementia. The clinical evaluation, carried out at the start as well as halfway through (45 days) and at the end of treatment (90 days), was expressed by psychometric tests (modified Parkside behaviour rating scale, Sandoz clinical assessment geriatric scale, word fluency test, Hamilton's rating scale of depression, narration subtest of Wechsler memory scale). Both treatments produced a definite symptomatic improvement and showed a very good tolerability. The results suggest that in most tests alpha-GPC possessed a statistical higher efficacy and an overall more satisfactory activity assessed by both patients and investigators compared with CDP.

Aged↗
PubMed1980

Origin of glycerylphosphorylcholine, inositol, N-acetylaminosugar, and prostaglandins in human seminal plasma and their effects on sperm metabolism.

The origin of glycerylphosphorylcholine (GPC), N-acetylaminosugar, inositol, and prostaglandins in human seminal plasma was investigated by correlating the concentration of these components in split ejaculates with known marker constituents. Fructose and acid phosphatase were selected as markers of the secretory activity of the seminal vesicles and prostate gland, respectively, and spermatozoa indicated epididymal origin. The concentration of fructose was lowest in the first fraction of the semen and increased to a maximum in the final portion. Prostaglandins E and F and N-acetylaminosugar values closely followed this pattern, indicating that these components originate in the seminal vesicles. The concentration of spermatozoa was high in the first two fractions, decreasing to a minimum in the final fraction. The distribution of GPC was similar to that of the spermatozoa, indicating that the epididymis secretes this compound. Inositol levels were similar in all fractions, indicating that it is probably present in epididymal, vesicular, and prostatic fluid. Human spermatozoa were unable to utilize N-acetylglucosamine or inositol. High concentrations of some prostaglandins (100 micrograms/ml of PGF1 alpha, 15S 15 met. F2 alpha, PGA1, and PGA2) depressed the endogenous oxygen uptake of human spermatozoa.

Acetylglucosamine↗