The interconversion of zearalenone and zearalenol by rat erythrocytes in vitro has been investigated. The major metabolite obtained by incubating zearalenone with erythrocytes or whole blood from Sprague-Dawley rats was alpha-zearalenol. beta-Zearalenol was also formed but at levels several times lower than those of alpha-zearalenol. In the cell-free haemolysate NADPH was much more effective than NADH as a co-factor in the reduction of zearalenone. The maximal transformation of zearalenone to zearalenol by haemolysates occurred at pH 8.0. Both NAD+ and NADP+ were effective as co-factors in the oxidation of alpha-zearalenol to zearalenone. However, only NADP+ was effective as a co-factor in the oxidation of beta-zearalenol. Conversion of alpha-zearalenol and beta-zearalenol to the corresponding epimer was observed in both erythrocyte suspensions and in cell-free haemolysates. The significance of these findings to the metabolism of zearalenone in vivo is discussed.

Animals↗

PubMed1984

Abundance of dimethylamine in seafoods: possible implications in the incidence of human cancer.

Levels of secondary and primary amines in various squids and other seafoods were determined by the newly developed dabsylation-HPLC method. Ammonia and dimethylamine were found in all of the seafoods analyzed, and some of them also contained methylamine, isobutylamine, ethylamine, and/or diethylamine. Extremely high levels of dimethylamine and methylamine were detected in all squids analyzed and in certain other seafoods. Very high activity of trimethylamine oxidase was observed in fresh squid tissue. Pyrolysis of sarcosine HCl and trimethylamine HCl yielded high levels of dimethylamine and methylamine. Various cooking conditions (extracting, frying, and broiling) had profound effects on amine content. Broiling was found to elevate the amine contents in most seafoods.

Ammonia↗

PubMed1984

Reversible hepatic black pigmentation and enzyme alteration induced by prolonged feeding of high dose of crocin dyes in rats.

Crocin dyes, isolated from Gardenia jasminodes, did not affect hepatic function when they were orally administered to rats in a daily dose of 50 mg/kg for 8 days, but could induce acute hepatic discoloration. A high dosage of 100 mg/kg for 2 weeks could induce both hepatic damage and black pigmentation, but a lower dose of 100 mg/kg for 40 days did not. Rats fed on diet containing 1% of crocin dyes for four months were shown to have mild hepatic functional disorders and pigmentation. The black pigmentation of the liver and the acute hepatic damage associated with the discoloration were completely reversible. During the period of hepatic pigmentation caused by high dose of crocin dyes, the urine had abnormally increased porphyrin excretion and tended to display a blackish green color. The skin also appeared purplish black. The mechanism of black pigmentation seemed to correlate with the gradual accumulation of crocin dyes. In summary, the crocin dyes have a very low toxicity in rats even in high experimental dosage which would hardly happen in human practice. It is therefore suggested that the crocin dyes are safe for coloring foods.

Administration, Oral↗

PubMed1984

N-nitrosophenacetin: its synthesis, characterization, mutagenicity, and teratogenicity.

Reaction of phenacetin (CAS: 62-44-2; p-acetophenetidide) with nitrous fumes (N2O3) in glacial acetic acid at 0-5 degrees C yields N-nitrosophenacetin (NP), 2-nitrophenacetin, N-nitroso-2-nitrophenacetin (NNP), and other compounds. Both NP and NNP are fairly stable at low temperature (-30 degrees C) but extremely labile at ambient temperature. NP (median lethal dose to Sprague-Dawley rat: 21 mg/kg body wt) is 80 times more toxic than its parent compound phenacetin and is directly mutagenic to bacterial cells including Salmonella typhimurium and Sarcina lutea. The mutagenicity of NP is comparable to that of N-methyl-N'-nitro-N-nitrosoguanidine [(MNNG) CAS: 70-25-7; 1-methyl-3-nitro-1-nitrosoguanidine] and requires no microsomal metabolic activation. The teratogenic potential of NP was studied in White Leghorn chick embryos given a single dose of 5-15 micrograms/egg on day 6 of incubation. A low incidence of exencephaly and eyelid defect and a high incidence of feather and claw malformations were found in the treated group; no such malformed embryos were found in the control group. The teratogenicity of NP was found to be weaker than that of MNNG, but stronger than that of N-methyl-N-nitrosourea (CAS: 684-93-5), dimethylnitrosamine (CAS: 62-75-9; N-nitrosodimethylamine), and diethylnitrosamine (CAS: 15-18-5; N-nitrosodiethylamine).

Abnormalities, Drug-Induced↗

PubMed1984

Derangement of plasma amino acids in severely ill patients.

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Adult↗

PubMed1983

High concentrations of dimethylamine and methylamine in squid and octopus and their implications in tumour aetiology.

The levels of the common secondary amines in various squid, in octopus and in 17 other seafoods were determined by HPLC. Ammonia and dimethylamine were found in all of the seafoods tested and some of them also contained methylamine and/or ethylamine. Particularly high levels of dimethylamine (946-2043 ppm) and methylamine (38-255 ppm) were detected in various species of squid and in the octopus. Reaction of nitrite in acidic medium with aqueous extract of squid yielded appreciable amounts of N-nitrosodimethylamine. The optimum pH for this reaction was around 2.4. Dimethylamine in dried squid tissues was readily extracted with water or 1% sodium carbonate solution. Heat treatment of dried squid at 200 degrees C was found to increase its amine content dramatically. It appeared that pyrolytic decarboxylation of some amino acids might cause this increase. Squid is a popular seafood in Japan and other oriental countries. The high incidence of stomach cancer in Japan and China is thought by epidemiologists to be associated with traditional Japanese and Chinese diets. Our present finding that squid and other seafoods contain unusually high levels of dimethylamine and other amines adds to the evidence that dietary factors may have an important role in the aetiology of stomach cancer and other gastro-intestinal tumours.

Animals↗

PubMed1982

Chromophoric determination of putrescine, spermidine and spermine with dabsyl chloride by high-performance liquid chromatography and thin-layer chromatography.

A fast and sensitive method for the determination of putrescine, spermidine, spermine and ammonia by high-performance liquid chromatography (HPLC) with dabsyl chloride is described. These compounds are converted to their chromophoric dabsyl derivatives and are separated by a normal-phase chromatographic column (mu Porasil, 10 microgram) with 2% acetone in chloroform as isocratic mobile phase. The sensitivity of the method is 20 pmoles. The present method was shown to be a straightforward procedure for estimating polyamines in various rat tissues. The chromophoric derivatives of polyamines are also well separated by thin-layer chromatography (TLC) on silica gel, and the combination of the HPLC and TL C procedures provides a reliable method for qualitative and quantitative analysis of polyamines.

Animals↗

PubMed1982

Effects of lactobacillus, antacids and antibiotics on the levels of nitrite in the gastro-intestinal tracts of rats fed sodium nitrate.

No nitrite was detected in the tissues or contents of the gastro-intestinal tracts of normal rats but after 2 wk on a diet containing 0 . 5% sodium nitrate the levels of nitrite in the stomach, small intestine and large intestine contents were 0 . 83%, 1 . 64-2 . 07 and 0 . 83 micrograms/g of contents respectively. Concurrent administration of 2% Lactobacillus preparation and 0 . 5% sodium nitrate in the diet for 2 wk further increased the nitrite levels in the intestines and slightly increased the level in the stomach. The elevation of nitrite levels induced by sodium nitrate administration was potentiated considerably by combined treatment with sodium bicarbonate and hetacillin producing nitrite levels of 3 . 16, 2 . 93-5 . 18 and 1 . 96-2 . 34 micrograms/g of the contents of the stomach, small intestine and large intestine respectively. Like hetacillin, minomycin and thiamphenicol also potentiated the nitrite production whereas amikacin (another antibiotic) strongly inhibited the formation of nitrite in the stomach. The different effects of the antibiotics may be due to their selective activities on the various microbes. The results indicate that the levels of nitrite in the gastro-intestinal tract are regulated by the level of nitrate intake, the population of microflora and the gastric pH. The safety of combined medication with antacids, antibiotics and Lactobacillus preparations in man deserves further investigation.

Animals↗

PubMed1982