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PubMed1981

A gas chromatographic method for the determination of N-acetyl-L-aspartic acid, N-acetyl-alpha-aspartylglutamic acid and beta-citryl-L-glutamic acid and their distributions in the brain and other organs of various species of animals.

A simple and sensitive gas-chromatographic method for the determination of N-acetyl-L-aspartic acid (NA-Asp), N-acetyl-alpha-aspartylglutamic acid (NA-Asp-Glu) and beta-citryl-L-glutamic acid (beta-CG) was developed. The organ, regional and phylogenetic distributions of these compounds were studied. NA-Asp and NA-Asp-Glu were highly concentrated in nervous tissue, and less than 1% of the amounts in the nervous tissues were found in non-nervous organs. These two compounds showed a reciprocal relationship in their regional distribution in mature brains, but such a relationship was not evident or was even reversed in immature brains. The two compounds also showed different developmental changes in different regions of the brain. Fish brain contained a relatively high concentration of NA-Asp, but only a trace amount of NA-Asp-Glu. By contrast, a 10 times higher concentration of NA-Asp-Glu than NA-Asp was found in frog brain. Reptilian brain contained similar amounts of each compound. Avian and mammalian brain had NA-Asp at a roughly 10 times higher concentration than NA-Asp-Glu. beta-CG occurred at the highest concentration in the immature brain of rat and guinea pig, but disappeared in the mature brains. The adult frog brain, however, contained a large amount of beta-CG. In the adult rat, testis contained the highest concentration of beta-CG.

Aging↗
PubMed1981

Developmental changes of N-acetyl-L-aspartic acid, N-acetyl-alpha-aspartylglutamic acid and beta-citryl-L-glutamic acid in different brain regions and spinal cords of rat and guinea pig.

The developmental changes of N-acetylaspartic acid (NA-Asp), N-acetyl-alpha-aspartylglutamic acid (NA-Asp-Glu), and beta-citryl-L-glutamic acid (beta-CG) have been examined in the cerebrum, cerebellum, brain stem and spinal cord of both rat and guinea pig by the gas chromatographic method developed in our studies. A rapid increase in the concentration of NA-Asp was observed postnatally in every region of the rat brain. On the other hand, all regions of guinea pig brain showed the prenatal increases. NA-Asp-Glu showed a different developmental profile, depending on region of the brain, in the two species. The concentration of NA-Asp-Glu remained constantly low during brain maturation in the rostral regions. In the caudal portions it showed a marked increase during maturation and reached a high level in the adult brain. The concentration of beta-CG was highest at birth in all regions of rat brain and rapidly decreased by 20 days after birth and remained low thereafter. The rapid decrease occurred in the guinea pig during the foetal period, and beta-CG content decreased to an adult level at birth.

Aging↗
PubMed1972

Oxidation of nicotinic acid by a Bacillus species: regulation of nicotinic acid and 6-hydroxynicotinic acid hydroxylases.

The first two enzymes employed by a Bacillus species for the dissimilation of nicotinic acid are coordinately induced. The inducer of the enzymes appears to be 6-hydroxynicotinic acid, the product of the first enzyme in the pathways. Synthesis of the enzymes is repressed by glucose when ammonium is present in the medium, but not when nicotinic acid is the sole nitrogen source. The possible significance of the coordinate induction and unusual repression is discussed.

Bacillus↗
PubMed1977

N-terminal amino acid sequences of acid proteases: acid proteases from Penicillium roqueforti and Rhizopus chinensis and alignment with penicillopepsin and mammalian proteases.

The amino-terminal sequence (33 residues) of the acid protease from Penicillium roqueforti has been determined with an automated sequencer. The amino-terminal sequence of Rhizopus pepsin (published by Sepulveda, P., Jackson, K. W. & Tang, J. (1975) Biochem. Biophys. Res. Commun. 63, 1106-1112) has been extended from 27 residues to 39 residues. Also, it was found that two forms of Rhizopus pepsin differ in position 15, where Rhizopus pepsin I has an isoleucine and Rhizopus pepsin II a valine residue. The new sequences have been aligned with the amino-terminal sequences of penicillopepsin (EC 3.4.23.7), pig pepsin (EC 3.4.23.1), calf chymosin (EC 3.4.23.4), human pepsin (EC 3.4.23.2), human gastricsin (EC 3.4.23.3), and cow pepsin (EC 3.4.23.1). Residues 31-35 (numbering based on pig pepsin, Tang, J., Sepulveda, P., Marciniszyn, Jr., J., Chen, K.S.C., Huang, W.-Y. , Tao, N., Liu, D. & Lanier, P. (1973) Proc. Natl. Acad. Sci. U.S.A. 70, 3437-3739) are identical in all enzymes. This section contains one of the two aspartic acids (Asp-32) implicated in the active site. The similarity of the sequences provides strong evidence for the homology of these acid proteases.

Amines↗
PubMed1984

Pre-proglucagon messenger ribonucleic acid: nucleotide and encoded amino acid sequences of the rat pancreatic complementary deoxyribonucleic acid.

Glucagon, a pancreatic peptide hormone of 29 amino acids that regulates carbohydrate, fat, and protein metabolism, is one of a family of structurally similar regulatory peptides which include GH-releasing hormone, vasoactive intestinal peptide, secretin, and gastric inhibitory peptide. The synthesis of glucagon involves its specific proteolytic cleavage from preproglucagon, a large polyprotein precursor. To facilitate analyses of the cellular processing of pre-proglucagon and to begin studies of the regulation of glucagon gene expression in the rat, we have cloned and sequenced two cDNAs derived from rat neonatal pancreas. The cDNAs represent close to the entire transcriptional sequence of the glucagon gene and encode a pre-proglucagon of 180 amino acids. The coding region of pre-proglucagon contains, in addition to the sequence of glucagon, the sequences of two peptide domains that are related in their structures to glucagon. Glucagon and the two glucagon-like peptides are flanked in the precursor by pairs of basic amino acids characteristic of the sites that are cleaved during the posttranslational processing of pro-hormones. Northern blot analyses indicate the presence of a single mRNA of 1400 +/- 100 nucleotides in the rat pancreas, and results of Southern blotting of rat liver genomic DNA are consistent with the existence of a single chromosomal gene. Comparisons of the nucleotide sequence of the rat pre-proglucagon cDNA with those of the two pre-proglucagons of the anglerfish pancreas encoded by two separate genes indicate that the pre-proglucagon genes probably evolved by intragenic duplications of a DNA segment corresponding to the coding sequences of glucagon and the glucagon-like peptides.

Amino Acid Sequence↗
PubMed1986

[Bioavailability of a valproic acid preparation. The relative bioavailability of enteric-resistant valproic acid preparations in tablet form with simultaneously administered tetradeuterated valproic acid as the bioavailability reference].

The relative bioavailability was measured for the 150-, 300-, and 600-mg enteric coated Leptilan tablets (valproic acid, sodium salt) using a new method. Simultaneously an equimolar amount of a tetradeuterated valproic acid - di-(2,3-dideutero-n-propyl)-acetic acid - was given as an aqueous solution of the sodium salt. This methodology excludes effects on the two partial pharmacokinetics caused by time-dependent intraindividual variations of the metabolising capacity or other biochemical or physiological changes in the body of the volunteer. Therefore, this methodology gives already reliable data for bioavailability when using only small numbers of volunteers. The relative bioavailability of the enteric coated Leptilan tablets was 95.5 +/- 0.6%, 104.4 +/- 7.6%, and 100.7 +/- 2.4% (mean from experiments with 3 volunteers each) for the 150-, 300-, and 600-mg tablets respectively.

Adult↗
PubMed1983

Acid-base status of biological fluids: amount of acid, kind of acid, anion-cation difference, and buffer value.

A formal concept of amount of substance of 'acid' and 'base' is proposed which is based upon the change in extent of protolytic equilibria in an arbitrary reference state for the components of the system concerned and equally consistent with the Brønsted-Lowry terminology, the older medical 'anion-cation' terminology, and the operational principle of titration. It is shown how this concept allows formulations of the 'acid-base status' of biological fluids in accordance with various types of physiological, biochemical, or clinical problems. Finally, a general expression for buffer value is presented which is valid for any acid, base, or ampholyte at any pH.

Acid-Base Equilibrium↗
PubMedDate not supplied

[Amino acid composition of preparations acid-soluble skin collagen and free amino acids in rat serum under loading with valine and methionine].

The valine and methionine loading against a background of protein-free diet evokes interrelated changes in amino acid composition of acid-soluble skin collagen preparations and free amino acids pool of blood serum in rats. The isolated collagen preparations also differ essentially from the normal preparations in the content of disulphide groups and elution profiles.

Amino Acids↗
PubMed1995

Effects of retinoic acid and gamma-interferon on expression of retinoic acid receptor and cellular retinoic acid-binding protein in breast cancer cells.

Retinoids and gamma-interferon (IFN-gamma) have been demonstrated to synergistically amplify growth inhibition in cultured breast cancer cells. Since IFN-gamma enhances effects mediated by retinoids more than vice versa, we focused our investigations on the mRNA expression of cellular retinoic acid-binding proteins (CRABPs) and retinoic acid receptors (RARs), since these are the key molecules that mediate retinoid action. Synergistic inhibition of cell proliferation under treatment with 9-cis-retinoic acid and IFN-gamma was detected in the three breast cancer cell lines MCF-7, SKBR-3, and even in the RA-resistant BT-20 cells. RAR-alpha and RAR-gamma mRNA were observed in all cell lines, whereas RAR-beta was not detectable. CRABP I message was expressed in MCF-7 cells only, but CRABP II was found in all three breast cancer cell lines. IFN-gamma (10 ng/ml) increased RAR-gamma expression but had no influence on RAR-alpha, whereas RAR-beta was not detectable in any of the cell lines. RA (1 microM)-mediated CRABP II increase was suppressed by IFN-gamma (10 ng/ml). These observations indicate that IFN-gamma-mediated increase in RAR-gamma and suppression of RA-mediated CRABP II activation may play a role in synergistic inhibition of proliferation in breast cancer cell lines.

Breast Neoplasms↗
PubMedDate not supplied

Some central effects of kynurenic acid, 7-chlorokynurenic acid and 5,7- dichloro-kynurenic acid, glycine site antagonists.

Strychnine-insensitive glycine site is one of a few binding sites of NMDA receptor complex. The aim of these study was to find out whether compounds regarded as glycine antagonists-kynurenic acid (KA), 7-chlorokynurenic acid (7-CKA), 5,7-dichlorokynurenic acid (5,7-DCKA) evoke the effects analogous to those of the NMDA receptor antagonist, CGP 37849 (or MK-801) and/or can modulate the effects of the last compounds in rats. KA (but not 7-CKA, given ip) inhibited electroshock-induced seizures and increased the anticonvulsant effect of CGP 37849. CGP 37849-induced locomotor hyperactivity was enhanced by KA, 7-CKA (icv but not ip) and 5,7-DCKA. D-Amphetamine-induced hyperactivity was inhibited by KA as well as 7-CKA. In monoamine-depleted rats 7-CKA (but not KA) increased the antiakinetic effect of clonidine; the antiakinetic effect of L-DOPA was enhanced by 7-CKA and 5,7-DCKA, but not by KA. KA and 7-CKA did not change the spiperone-induced catalepsy but they attenuated the anticataleptic effect of CGP 37849; the studied drugs did not change the anticataleptic effect of MK-801. 7-CKA given icv did not influence the spiperone-induced catalepsy as well as the anticataleptic effect of CGP 37849. In the forced swimming test KA, given once, prolonged (50 mg/kg) or did not change (200 and 300 mg/kg) the immobility time. 7-CKA did not affect the immobility time in this model. When given three times KA (200 mg/kg) and 7-CKA (20 mg/kg) reduced the immobility time; the lower doses of KA and 7-CKA prolonged or did not change the immobility time, respectively. Joint injection with imipramine and KA (or 7-CKA) induced the decrease of immobility time (vs imipramine alone or glycine antagonist alone); in the case of joint injection with citalopram + KA (or 7-CKA), the time of immobility was prolonged or not changed. In conclusion, the obtained results point to similarities between glycine antagonists (kynurenine derivatives) and CGP 37849 and to the possibility of positive cooperation between the NMDA- and glycine-sites antagonists.

Amphetamine↗
PubMed1977

Maple syrup urine disease: branched-chain keto acid decarboxylation in fibroblasts as measured with amino acids and keto acids.

Branched-chain keto acid decarboxylase activity in skin fibroblasts from control subjects and from patients with classical and variant forms of maple syrup urine disease (MSUD) was measured with leucine and alpha-ketoisocaproic acid. When the keto acid was used as substrate in high concentrations (more than 5 mM), the three groups overlapped extensively, even classical cases of MSUD exhibiting decarboxylase activity. With leucine as substrate, decarboxylase activity plateaued at about 1.5 mM, and the three groups could be clearly differentiated. Classical cases of MSUD had minimal or no decarboxylase activity.

Caproates↗
PubMed2002

Trans isomeric octadecenoic acids are related inversely to arachidonic acid and DHA and positively related to mead acid in umbilical vessel wall lipids.

Long-chain PUFA play an important role in early human neurodevelopment. Significant inverse correlations were reported between values of trans isomeric and long-chain PUFA in plasma lipids of preterm infants and children aged 1-15 yr as well as in venous cord blood lipids of full-term infants. Here we report FA compositional data of cord blood vessel wall lipids in 308 healthy, full-term infants (gestational age: 39.7 +/- 1.2 wk, birth weight: 3528 +/- 429 g, mean +/- SD). The median (interquartile range) of the sum of 18-carbon trans FA was 0.22 (0.13) % w/w in umbilical artery and 0.16 (0.10) % w/w in umbilical vein lipids. Nonparametric correlation analysis showed significant inverse correlations between the sum of 18-carbon trans FA and both arachidonic acid and DHA in artery (r = -0.38, P < 0.01, and r = -0.20, P < 0.01) and vein (r = -0.36, P < 0.01, and -0.17, P < 0.01) wall lipids. In addition, the sum of 18-carbon trans FA was significantly positively correlated to Mead acid, a general indicator of EFA deficiency, in both artery (r = +0.35, P < 0.01) and vein (r = +0.31, P< 0.01) wall lipids. The present results obtained in a large group of full-term infants suggest that maternal trans FA intake is inversely associated with long-chain PUFA status of the infant at birth.

8,11,14-Eicosatrienoic Acid↗
PubMed1990

Metabolism of [3H]arachidonic acid- and [14C]linoleic acid-labelled chylomicrons in essential fatty acid-deficient rats.

Mesenteric duct chylomicrons labelled with [3H]arachidonic (20:4) and [14C]linoleic (18:2) acid were injected intravenously into essential fatty acid-deficient (EFAD) and control rats. The rats were killed after 5, 10, 20 and 240 min, and serum and different organs were analysed for radioactivity of different lipid classes. 3H and 14C in the triacylglycerol (TG) and phosphatidylethanolamine (PE) fractions were cleared from blood faster in the EFAD than in the control rats. The incorporation of [14C]18:2 into liver and heart phospholipids was increased compared to control rats at all time intervals, the increase in the incorporation of [3H]20:4 being less pronounced. Furthermore, the total incorporation of [14C]18:2 was increased in the heart of the EFAD group. The increased incorporation into phosphatidylcholine (PC) and particularly into PE was observed already at 5-20 min, whereas a marked increase in the 14C radioactivity of cardiolipin occurred between 20 and 240 min. The 3H and 14C radioactivity per g white adipose tissue was lower in the EFAD group than in the controls. After 5-20 min there were no differences between the groups in the lipid radioactivity of the stomach and the small and the large intestine. In the upper small intestine, the 3H radioactivity in both groups and the 14C radioactivity in the EFAD group increased markedly between 20 and 240 min. The study demonstrates an increased plasma clearance and an efficient hepatic uptake and initial incorporation into PC and PE of chylomicron [14C]18:2 and [3H]20:4 in EFAD rats. In these rats a marked selective transfer of [14C]18:2 to cardiolipin from other tissue lipids occurred with time. In addition, the study demonstrates a preferential transfer of injected [3H]20:4, and in EFAD rats also of [14C]18:2, into lipids of the upper small intestine, possibly by secretion of [3H]20:4 and [14C]18:2 in bile phospholipids.

Animals↗
PubMed1987

Membrane-directed effects of the plant hormones abscisic acid, indole-3-acetic acid and 2,4-dichlorophenoxyacetic acid.

This study examines two ways plant hormones might influence membrane processes, effects on overall permeability and modifications of specific ion channels. Abscisic acid (ABA) and indole-3-acetic acid (IAA) greatly enhanced erythritol permeability in mixed egg lecithin bilayers. In single component dioleoylphosphatidylcholine bilayers ABA was less effective than IAA, while 2,4-dichlorophenoxyacetate (2,4-D) did not affect either system or alter their ABA response. In Myxicola axons ABA and IAA had no effect, while 2,4-D (10 uM) caused a depolarizing shift of voltage-dependent Na+ and K+ activation by 25 +/- 4 mV and 15 +/- 3 mV, consistent with internal negative surface charge changes of -0.002 e-/A2 and -0.0007 e-/A2. We conclude that both generalized and ion channel-directed effects may link plant hormones and intracellular regulation.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1996

Evidence for release of glutamic acid, aspartic acid and substance P but not gamma-aminobutyric acid from primary afferent fibres in rat spinal cord.

In vitro superfusion release experiments and autoradiography were carried out on spinal cords of neonatally capsaicin-treated rats. Electrical and chemical stimulations significantly increased the release of aspartate, glutamate and gamma-aminobutyric acid (GABA) from hemisected dorsal horn slices of vehicle-treated animals. In capsaicin-treated rats, the evoked release of aspartate, glutamate and substance P but not GABA, were significantly lower. Capsaicin (1 microM) stimulated the release of aspartate and glutamate, as reported for substance P, in control slices but this effect was not as apparent in tissues from capsaicin-treated rats. Evoked GABA release was not affected in either case. alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), kainate, dizocilpine and GABAB binding sites were highly localised in the substantia gelatinosa. Capsaicin treatment did not affect the affinity of the binding sites in all four cases but significantly reduced the density of kainate, dizocilpine and GABAB binding sites. The data suggest that capsaicin-sensitive primary afferent fibres release aspartate, glutamate and Substance P following high-intensity stimulations and that this release might be modulated by presynaptic glutamate and GABAB receptors present on these terminals.

Afferent Pathways↗
PubMed1973

Metabolism of steroid and amino acid moieties of conjugated bile acids in man. 3. Cholyltaurine (taurocholic acid).

After oral administration of [2,4-(3)H]-cholyl[(35)S]taurine to eight healthy subjects with indwelling nasoduodenal tubes, the specific activity of the cholyl and taurine moieties and the distribution of radioactivity in biliary bile acid and urinary metabolites, as well as total urinary and fecal (35)S and (3)H, were measured at intervals for 4-8 days. Similar measurements were made after [(35)S]taurine was given orally or intravenously or instilled into the distal intestine. The daily fractional turnover rate of the taurine moiety of cholyltaurine was low and similar to that of the cholyl moiety, indicating that deconjugation occurring during enterohepatic cycling was less than half that previously observed for glycine-conjugated bile acids. Some of the cholyl moiety was absorbed but, since reconjugation occurred predominantly with glycine, little reincorporation into the cholyltaurine pool was observed. Some of the taurine moiety was also absorbed intact but entered large taurine pools, and little reincorporation into the cholyltaurine pool was seen. Oral administration of taurine expanded the cholyltaurine pool and induced a decrease in the fractional turnover rate of the cholyl moiety of cholyltaurine, interpreted to indicate a greater reincorporation of the cholyl moiety because of increased reconjugation with taurine. Taurine moiety not absorbed as taurine appeared to be absorbed largely as sulfate which, like taurine, entered large endogenous pools. Little fecal excretion of (35)S occurred. (35)S was excreted in urine as taurine and sulfate, and excretion in the first 24 h (as percentage of administered dose) correlated highly (r = 0.93) with the daily fractional turnover rate of the taurine moiety. When taurine was instilled into the distal intestine, it appeared as such in plasma, but the more distal the site of instillation, the greater the fraction of urinary (35)S present as sulfate. The [(35)S]sulfate appeared to have come from bacterial degradation of [(35)S]taurine because, when [(35)S]taurine was given intravenously, (35)S was excreted in urine chiefly as [(35)S]taurine with little SO(4)=(-)[(35)S] being present.

Bile↗
PubMed1989

Protein binding of quinolonecarboxylic acids. II. Spectral changes on the interaction of cinoxacin, nalidixic acid and pipemidic acid with human and rat albumins.

The interaction of cinoxacin (CINX), nalidixic acid (NA), and pipemidic acid (PPA) with human and rat serum albumins (HSA and RSA) was studied by UV difference absorption and circular dichroism (CD) spectroscopy. CINX and NA bound to the albumins and generated difference absorption and induced CD (ICD) spectra. The difference absorption spectral data explained reasonably our previous observations that CINX bound to HSA more weakly than NA, but to RSA as strongly as NA. We used a quantity delta epsilon/epsilon, designated as relative molar difference absorbance, at positions corresponding to the longest wavelength peaks in the difference spectra. The quantity was found to correlate linearly with percent bound to both HSA and RSA, but with different slopes, from which the binding site for CINX and NA in RSA was supposed to provide a much more nonpolar environment than that in HSA. The magnitude of ICD bands observed at 371 nm for CINX and at 342-348 nm for NA corresponded to the binding degrees of these drugs to both albumins. Anisotropy factors for the ICD bands at 350-271 nm for CINX and 320-348 nm for NA were approximately similar between HSA and RSA, suggesting a similar ability to generate the ICD spectra in these wavelength regions upon binding to the albumins. Spectral results for PPA in albumin solutions showed little or no binding of this drug to HSA and RSA. PPA existed as a betaine form in neutral solution and its positively charged group acted as an unfavorable factor for binding to both albumins.

Animals↗
PubMed1993

Inhibition of aminopeptidases by phosphonic acid and phosphinic acid analogues of aspartic and glutamic acids.

More than 30 phosphonic and phosphinic acid analogues of aspartic and glutamic acids were synthesized in order to probe how the structural differences of these molecules were reflected in their ability to inhibit cytosolic (LAP) and microsomal (APM) aminopeptidases. Although most of the compounds studied were found to exert only a modest inhibitory effect, the studies provide some information on the structural requirements of the binding subsites and catalytic centers of both enzymes.

Aminopeptidases↗