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At least 19 recordsLinked to original sources
PubMed1984

Comparison of the carcinogenic effectiveness of N-nitrosobis(2-hydroxypropyl)amine, N-nitrosobis(2-oxopropyl)amine, N-nitroso(2-hydroxypropyl)(2-oxopropyl)amine, and N-nitroso-2,6-dimethylmorpholine in Syrian hamsters.

For examination of metabolic interrelationships in carcinogenesis between N-nitroso-2,6-dimethylmorpholine, N-nitrosobis(2-oxopropyl)amine (CAS: 60599-38-4), N-nitrosobis(2-hydroxypropyl)amine (CAS: 53609-64-6), and N-nitroso(2-hydroxypropyl) (2-oxopropyl)amine, each was given to a separate group of 20 female Syrian golden hamsters by gavage. All four compounds induced tumors of the pancreatic duct and lung tumors, but the incidences varied from one compound to another. In addition, N-nitrosobis(2-oxopropyl)amine and N-nitroso(2-hydroxypropyl)(2-oxopropyl)amine induced many hepatocellular and cholangiocellular neoplasms, which the other two compounds did not. On the basis of short time to death with tumors and the relatively low total dose administered, N-nitrosobis(2-oxopropyl) amine appeared to be the most potent carcinogen in the hamster among the four. N-nitroso(2-hydroxypropyl)(2-oxopropyl)amine was next in potency but was considerably weaker than N-nitrosobis(2-oxopropyl)amine. N-Nitroso-2,6-dimethylmorpholine, which was similar in potency to N-nitroso(2-hydroxypropyl) (2-oxopropyl)amine, however, did not induce a significant incidence of liver tumors of any type; and N-nitrosobis(2-hydroxypropyl) amine was considerably less potent than the other three compounds. These results did not support the opinion of N-nitroso(2-hydroxypropyl) (2-oxopropyl)amine as the proximate carcinogenic metabolite of all three compounds in the Syrian hamster but instead suggested that these compounds might have acted through formation of different and yet unknown carcinogenic intermediates.

Animals↗
PubMed1981

Microbial oxidation of amines. Distribution, purification and properties of two primary-amine oxidases from the yeast Candida boidinii grown on amines as sole nitrogen source.

1. The yeast Candida boidinii was grown on glucose as carbon source with a range of amines and amino acids as nitrogen sources. Cells grown on amines contained elevated activities of catalase. If the amines contained N-methyl groups, formaldehyde dehydrogenase, formate dehydrogenase and S-formylglutathione hydrolase were also elevated in activity compared with cells grown on (NH(4))(2)SO(4). 2. Cells grown on all the amines tested, but not those grown on urea or amino acids, contained an oxidase attacking primary amines, which is referred to as methylamine oxidase. In addition, cells grown on some amines contained a second amine oxidase, which is referred to as benzylamine oxidase. 3. Both amine oxidases were purified to near homogeneity. 4. Benzylamine oxidase was considerably more stable at 45 and 50 degrees C than was methylamine oxidase. 5. Both enzymes had a pH optimum in the region of 7.0, and had a considerable number of substrates in common. There were, however, significant differences in the substrate specificity of the two enzymes. The ratio V/K(app.) (m) increased with increasing n-alkyl carbon chain length for benzylamine oxidase, but decreased for methylamine oxidase. 6. Both enzymes showed similar sensitivity to carbonyl-group reagents, copper-chelating agents and other typical ;diamine oxidase inhibitors'. 7. The stoicheiometry for the reaction catalysed by each enzyme was established. 8. The kinetics of methylamine oxidase were examined by varying the methylamine and oxygen concentrations in turn. A non-Ping Pong kinetic pattern with intersecting double-reciprocal plots was obtained, giving K(m) values of 10mum for O(2) and 198mum for methylamine. The significance of this unusual kinetic behaviour is discussed. Similar experiments were not possible with the benzylamine oxidase, because it seemed to have an even lower K(m) for O(2). 9. Both enzymes had similar subunit M(r) values of about 80000, but the benzylamine oxidase behaved as if it were usually a dimer, M(r) 136000, which under certain conditions aggregated to a tetramer, M(r) 288000. Methylamine oxidase was mainly in the form of an octamer, M(r) 510000, which gave rise quite readily to dimers of M(r) 150000, and on gel filtration behaved as if the M(r) was 286000.

Benzylamine Oxidase↗
PubMed1990

Determination of amines, amine metabolites and some amine metabolizing enzymes by high performance liquid chromatography.

Some useful high performance liquid chromatographic methods for the determination of amines, amine metabolites and amine metabolizing enzymes are described. These include the separation of tyramine in wines and beers, determination of tryptamine in urine, assay of monoamine oxidase and catechol-O-methyltransferase and analysis of amine-aldehyde condensation products.

Aldehydes↗
PubMed1989

Carcinogenicity of N-nitroso(2-hydroxypropyl)(2-oxopropyl)amine, N-nitrosobis(2-hydroxypropyl)amine and cis-N-nitroso-2,6-dimethylmorpholine administered continuously in the Syrian hamster, and the effect of dietary protein on N-nitroso(2-hydroxypropyl)(2-oxopropyl)amine carcinogenesis.

The effect of continuous week-long administration of the three pancreatic carcinogens N-nitroso(2-hydroxypropyl)(2-oxopropyl)amine (HPOP), N-nitrosobis(2-hydroxypropyl)amine (BHP), and cis-N-nitroso-2,6-dimethylmorpholine (cis-NNDM), by a s.c. implanted osmotic pump, was examined in Syrian hamsters. HPOP at total doses of 220-250 mg/kg body weight induced ductal adenocarcinomas in the pancreas (41%), and cholangiomas (18%) and cholangiocarcinomas (18%) in the liver, 25 weeks following the initiation of treatment. Higher doses of HPOP resulted in severe hepatic injury and increased mortality (LD50 = 280 mg/kg). Cis-NNDM and BHP were less toxic than HPOP and induced pancreatic lesions at doses of 950 mg/kg. These data document that a week-long schedule of continuous administration of HPOP for the induction of pancreatic cancer compares favorably with those involving weekly injections. Application of this model to study the effect of dietary protein in HPOP-induced carcinogenicity showed that the number of cystic, intermediate and tubular complexes in the pancreas was significantly higher in animals fed a 20% as compared to an 8% protein diet 2 weeks prior to HPOP administration. Furthermore, the incidence of pancreatic adenocarcinomas and in situ carcinomas was only 13% in the hamsters fed the low-protein diet as compared to 46% in those fed the high-protein diet.

Adenocarcinoma↗
PubMed1991

Uptake of N-(4'-pyridoxyl)amines and release of amines by renal cells: a model for transporter-enhanced delivery of bioactive compounds.

The importing of vitamin B6 by renal proximal tubular cells from the rat is facilitated and Na(+)-dependent and reflects specificity for the meta-phenolate pyridinium structure with a 5-hydroxymethyl function. This transporter can, however, accept competitively each of the natural nonphosphorylated vitamers (pyridoxine, pyridoxamine, and pyridoxal) and other B6 analogues differing only in the groups at position 4. A series of N-(4'-pyridoxyl)amines was synthesized by sodium borohydride or boro[3H]hydride reduction of aldimines formed by condensing the amines with pyridoxal. The unlabeled B6-secondary amine compounds were found to competitively inhibit the uptake of [4'-3H]pyridoxine by the renal cells. Moreover, the 3H-labeled N-(4'-pyridoxyl)amines were shown to enter the cells by the process facilitated by the B6 transporter. Upon entry the labeled compounds were converted to N-(5'-phospho-4'-pyridoxyl)amines in a reaction catalyzed by pyridoxal kinase, an enzyme that tolerates considerable functional variation in position 4 of the B6 structure. The 5'-phosphates were subsequently converted within the cell to pyridoxal 5'-phosphate with liberation of the original amine in a reaction catalyzed by pyridoxamine (pyridoxine) 5'-phosphate oxidase, an enzyme with broad specificity for 4'-substituted amines on the 5'-phospho-B6 structure. This system illustrates how knowledge of transporter specificity can permit design of a compound with potential biologic activity. A drug or other intracellular effector may be piggybacked onto a transported solute (e.g., vitamin or other nutrient) that gains facilitated entry to a cell and is, thereafter, metabolized to release the active compound.

Amines↗
PubMed1986

Photochemical linking of primary aromatic amines to carrier proteins to elicit antibody response against the amine haptens.

Two chemical methods, diazocoupling and reaction with isocyanates, are commonly used to conjugate primary aromatic amines with carrier proteins in order to elicit antibody responses against the aromatic amine haptenic group. Limitations of these conjugation techniques include the requirement for specific functional groups on the carrier protein which generally limits the degree of haptenic substitution obtainable, the many possible side reactions yielding hapten-hapten and carrier-carrier conjugates which waste valuable materials and lower desired hapten-carrier conjugate yields, and, in some cases, conjugation conditions which may denature the carrier protein (e.g., alkaline coupling conditions). We report here a photolabeling approach for conjugating primary aromatic amines to carrier proteins which avoids some of the problems of other conjugation methods and which was used to elicit antibodies against the primary aromatic amine hapten. The method described here is of general application for coupling primary aromatic amines to the carrier proteins and circumvents many of the problems inherent in the isocyanate or diazocoupling methods. 3-Azido-N-ethylcarbazole (ANEC), the azido analog of 3-amino-N-ethylcarbazole, was conjugated to bovine serum albumin (BSA), human transferrin (TR), thyroglobulin (TH), poly-(lysine X tyrosine), and poly-(lysine X phenylalanine) using standard photolabeling procedures. After photolysis, the conjugated proteins or polypeptides were separated from the unbound products of ANEC photolysis on a Sephadex G-10 column. The conjugated proteins were extracted with isobutanol which demonstrated that approximately 20% of the ANEC was covalently coupled to the protein carriers and that the larger portion of the aromatic haptens was non-covalently and hydrophobically bound to the carriers. The ANEC-protein conjugates used for immunization demonstrated a total covalently and non-covalently bound ANEC epitope density of 90 per BSA, 107 per TR and 800 per TH molecule. Rabbits were immunized with the three conjugated proteins and the production of antibody specific for the 3-amino-N-ethylcarbazole hapten was demonstrated by enzyme-linked immunosorbent assay and by inhibition studies using hapten-carrier conjugates of free hapten. The results demonstrate that antibodies against aromatic amine haptens may be raised by immunizing animals with hapten-carrier protein conjugates produced by photolabeling. Since the coupling conditions are very mild and the functional group requirements are so general (requiring only the presence of C-H, N-H, C = O, C = S, or S-H bonds) most carrier proteins should be suitable for use in this method.(ABSTRACT TRUNCATED AT 400 WORDS)

Affinity Labels↗
PubMed1984

Cation exchange--a common mechanism in the storage and release of biogenic amines stored in granules (vesicles)? II. Comparative studies on sodium-induced release of biogenic amines from the synthetic weak cation-exchangers Amberlite IRC-50 and duolite CS-100 and from biogenic (granule-enriched) materials.

Superfusion of phenylethylamine-, noradrenaline- or histamine-charged weak (carboxyl) cation-exchangers (IRC-50 and Duolite CS-100) with isotonic NaCl caused a release of the amines. Similarly, bovine chromaffin granules and nerve granule preparations from bovine splenic nerve, rat vas deferens and rat corpus striatum released their amine(s) upon superfusion with the same solution. The courses of release from the synthetic and biogenic materials showed very similar characteristics and fitted the same exchange equations. The observations support the view that the matrices of the biogenic amine-storing granules have the properties of weak cation-exchanger materials with carboxyls as the cation-binding groups, and that the NaCl-induced release of the biogenic amines is due to cation exchange (Na+ in equilibrium Amine+). The possibility that amine release in vivo is based on cation exchange is discussed.

Adrenergic Fibers↗
PubMed1995

[Chemical carcinogenesis and cytochrome P450: carcinogenic aromatic amine-induced P450 and hepatocarcinogenic susceptibility to the aromatic amine in the rodent].

The N-hydroxyl and/or N-acetoxy derivatives of carcinogenic 4-aminoazo dyes, which were thought to be proximate and ultimate metabolites, were synthesized in our laboratory in 1975, and their chemical and biological characteristics were further examined. The results strongly supported the hypothesis that the metabolic conversions, N-hydroxylation and its O-acylation, of carcinogenic aromatic amines are important processes for their carcinogenicity. Carcinogenic aromatic amines such as heterocyclic aromatic amines and aminoazo dyes induced predominantly cytochrome P450IA2 (CYP1A2), which is responsible for the mutagenic activation and N-hydroxylation of the amines in the rodent. The induction rate and total activity of this enzyme were well correlated with sex, species, and target organ differences in hepatocarcinogenic susceptibility of animals to the aromatic amines. During hepatocarcinogenic process with an aromatic amine, the expression and induction of CYP1A2 decreased especially in preneoplastic liver cells as judged by the expression of a placental form of glutathione S-transferase.

Amines↗
PubMed1980

[On the problems in respect ot the formation of N-nitroso compound precursors when using alkylating agents in the fumigation of foodstuffs. I. Investigations of the formation of secondary amines by the action of ethylene oxide on primary amines and amino acids (author's transl)].

Special attention must be paid to the formation of secondary amines as precursors of nitrosamines as a possible consequence of the fumigation of foodstuffs with ethylene oxide. Investigations carried out in vitro show that secondary amines can result in various ways by reaction of the amine groups with ethylene oxide: 1. directly, by reaction of ethylene oxide with primary amines, 2. by reaction with amino acids followed by decarboxylation. Identification of the secondary amines produced by the reaction of ethylene oxide with primary amines or amino acids was carried out by means of thin layer chromatography. In this manner, the formation of methylamino ethanol, ethylamino ethanol and diethanolamine was demonstrated by the reaction of ethylene oxide with methylamine, ethylamine and ethanolamine. Furthermore, the reaction of ethylene oxide with glycine and serine followed by decarboxylation produced, depending upon the pH value, the compounds methylamino ethanol and diethanolamine.

Amines↗
PubMed1989

Semicarbazide-sensitive amine oxidase (SSAO) of the rat aorta. Interactions with some naturally occurring amines and their structural analogues.

The influence of a number of naturally occurring amines and their structural analogues has been examined on the metabolism of radiolabelled benzylamine (BZ) by the membrane bound semicarbazide-sensitive amine oxidase (SSAO) of the rat aorta. Only primary monoamines were effective in reducing the deamination of BZ. In the phenylethylamine series, addition of hydroxyl groups to the benzene ring decreased their potency as inhibitors while addition of a hydroxyl group at the beta position increased the inhibitory potency. Stereoselectivity of action was shown with octopamine, the L-isomer being the more active form. Kinetic analysis of these interactions showed predominantly competitive inhibition and kynuramine had the lowest Ki of 5.4 microM. The aliphatic monoamines, isoamylamine and isobutylamine both competed with BZ. 5-Hydroxytryptamine (5-HT) was the only amine that inhibited non-competitively. Direct evidence for metabolism by SSAO of some of the competing amines such as isoamylamine, phenylethylamine, tyramine and tryptamine was obtained by fluorimetric or radiochemical assays. The inhibitors clorgyline and (E)-2-(3',4'-dimethoxyphenyl)-3-fluoroallylamine (MDL 72145) were used to characterise the amine oxidase activity responsible for the deamination. Octopamine and phenylethanolamine (PeOH) were not SSAO substrates and inhibited BZ metabolism in the fluorimetric assay. It is possible that the activity of SSAO is controlled by octopamine released from sympathetic nerve endings or 5-HT released from platelets.

Allosteric Regulation↗
PubMed1992

Quantitative correlation of mutagenic and carcinogenic potencies for heterocyclic amines from cooked foods and additional aromatic amines.

Aromatic amines have long been recognized as animal and human carcinogens. Recently heterocyclic aromatic amines (thermic amines) have been found in small amounts in cooked foods, primarily meats, and have proven to be potent mutagens and rodent carcinogens. Availability of quantitative databases for mutagenic potency in Salmonella and for carcinogenic potency in rodents has made possible a study of ten heterocyclic thermic amines and 24 aromatic amines. Potencies on mutagenic and carcinogenic scales were significantly correlated. By multiple linear regression analysis and multivariate analysis of variance, two descriptive structural factors were found to modulate the two modes of biological response. These factors were number of rings and methyl substitution at carbon atoms. The quantitative correlation between mutagenic and carcinogenic potencies and the modulating structural factors suggest a significant similarity of molecular mechanisms and support the utility of the short-term bacterial assay in evaluating hazard levels.

Amines↗
PubMed1980

Copper, biogenic amines, and amine oxidases.

Amine oxidases have been classified in the past on the basis of either (a) the structural requirements in the substrate or (b) the tissue (or species) of origin, or both. As knowledge about the chemistry of these enzymes grows, their classification on the basis of chemical structure is becoming possible. Currently, many amine oxidases can be categorized according to whether they contain riboflavin (e.g. the monoamine oxidases -- EC 1.4.3.4) or copper (e.g. the amine oxidases of plasma and the diamine oxidases EC 1.4.3.6 -- found prominently in pig kidney cortex, placenta, and pea seedlings). The copper-linked oxidases are inhibited by cyanide and by semicarbazide. The nature of the carbonyl compound(s) in the various enzyme molecules is not yet known. Nutritional deficiencies of copper and treatment of animals with copper-chelating agents are reflected in reduced activity of one or more of these enzymes. The ultimate effects of copper deficiency and copper excess on amine metabolism in vivo are described.

Adrenalectomy↗
PubMed1990

Oxidative deamination of aliphatic amines by rat aorta semicarbazide-sensitive amine oxidase.

Rat aorta semicarbazide-sensitive amine oxidase (SSAO) exhibits very high affinity in the deamination of an homologous series of aliphatic amines of 1 to 18 straight chain carbon atoms. The Km value decreases substantially as the chain length of these amines increases. The Vmax values are higher for the short chain amines. Diamines are poor substrates for SSAO or are not acted upon by the enzyme. The substrate preference for SSAO differs from that for monoamine oxidase.

Amine Oxidase (Copper-Containing)↗