The formation of 2,3-dihydroxy-2,3-dihydro-aflatoxin B1 by the metabolism of aflatoxin B1 by liver microsomes isolated from certain avian and mammalian species and the possible role of this metabolite in the acute toxicity of aflatoxin B1

Neal, G.E.; Judah, David J.; Stirpe, Fiorenzo; Patterson, D.S.P.

doi:10.1016/0041-008x(81)90095-8

Cited by 76 publications

(31 citation statements)

References 26 publications

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“…It has been reported that rats have less GST activity toward AFBO than other rodents so there is a positive correlation between GST activity and AFB1 resistance (Monroe and Eaton, 1987;Hayes et al, 1998;Esaki and Kumagai, 2002). Although avian species are highly efficient in producing AFBO (Neal et al, 1981;Klein et al, 2000), they are not able to conjugate effectively the AFBO with GSH which indicates that they have low GST activity directed to this conjugation (Moss et al, 1983;Manson, 1995;Klein et al, 2000). Therefore, a mechanism that explains the wide variability of AFB1 sensitivity in poultry species has not been elucidated.…”

Section: Introductionmentioning

confidence: 92%

“…Presence of AFB1-dhd indicates that AFBO has been produced (Guengerich et al, 1998). Quantification of AFB1-dhd (which is an indirect measure of AFBO production) was made using AFB2 as standard since these two compounds have very similar fluorescence and spectral characteristics (these two metabolites are so similar in their spectrofotometric response that in the past they were misidentified (Neal et al, 1981)). Moreover, activation of AFB1 was determined as the GSH-trapped conjugate, which provides an accurate and quantitative measurement of AFBO formation (Monroe and Eaton, 1987).…”

Section: Microsomal and Cytosolic Incubationsmentioning

confidence: 99%

“…However, biotransformation may also lead to the formation of the AFB1-exo-8,9-epoxide (AFBO), the carcinogenic metabolite of AFB1 (Eaton and Gallagher, 1994). It has been documented that, unless avian species are stimulated through cytochrome P450 (CYP450) inducers, their microsomal fraction only produce AFBO and no other metabolite (Neal et al, 1981(Neal et al, , 1986Klein et al, 2000). However AFM1 has been identified in different avian tissues, indicating the ability of poultry species to produce this metabolite (Truckess et al, 1983).…”

Section: Introductionmentioning

confidence: 96%

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Microsomal and cytosolic biotransformation of aflatoxin B1 in four poultry species

Lozano

Diaz

2006

British Poultry Science

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1. This research evaluated differences in hepatic in vitro metabolism of aflatoxin B1 (AFB1) on selected avian species. 2. Microsomal and cytosolic liver fractions were obtained from chickens, ducks, quails and turkeys; eight males and eight females of each. 3. All microsomes studied produced AFB1-8,9-exo-epoxide (AFBO), a metabolite regarded as the active product of AFB1. Turkey microsomes produced 1.8 and 3.5 times more AFBO than quails and chickens microsomes, respectively. 4. Males from evaluated birds produced more AFBO than females, but statistically-significant differences between genders were observed only in ducks and turkeys. 5. The cytosolic fraction from all four species produced aflatoxicol (AFL). Turkey and duck hepatic cytosol produced more AFL than from quail and chickens. 6. It is known that turkeys are very sensitive to AFB1, quails are intermediate and chickens are particularly resistant; the differences in AFBO production shown in our study may help to explain the difference in vivo responses among turkeys, quail and chickens. 7. Moreover, AFL may be related to AFB1 toxicity; it was produced in larger amounts by hepatic cytosol from the more susceptible species. 8. Because AFBO production by microsomes in ducks was relatively low, it is possible that other toxicity mechanisms are involved in this highly susceptible species.

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Section: Introductionmentioning

confidence: 92%

Section: Microsomal and Cytosolic Incubationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

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Microsomal and cytosolic biotransformation of aflatoxin B1 in four poultry species

Lozano

Diaz

2006

British Poultry Science

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“…To 8, 9 εποξείδιο της AFE*! απαντάται σε δύο ισομερή, το ένδο-και έξω-εποξείδιο, από τα οποία το δεύτερο θεωρείται το πλέον τοξικό με σημα ντική ηπατοκυτταρική τοξική δράση (Berry 1988, Neal et al 1981). …”

Section: τοξικότητα των αφλατοξινώνunclassified

Aflatoxins in foods of animal origin

Govaris

2017

J Hellenic Vet Med Soc

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Anatoxins are produced by various types of Aspergillus spp. fungi in a wide variety of foods and feeds. Anatoxins are toxic to human and animals, acute and chronic. In humans, they can cause liver cancer, chronic hepatitis and cirrhosis. Among the four main aflatoxins (B1? B2, Gx and G2), aflatoxin Βχ (AFBi) is the most frequently found in feeds and the most toxic one. The most important aflatoxin in foods of animal origin is aflatoxin M4 (AFM4), which is the principal hydroxylated metabolite of AFB! AFM4 is mainly found in milk from lactating animals consuming feed contaminated with AFB^ Surveys carried on the occurrence of AFM4 in raw milk in various countries all over the world during the past 15 years, showed that contamination levels were low in European Union and USA, but high in certain countries of Africa, Asia and Latin America. Other global surveys on the occurrence of AFM4 in foods of animal origin (meat, eggs etch) showed that the level of the toxin is low as compared to milk and dairy products. European Union has set the maximum residual limit (MRL) for AFM4 of 0.05 μg/kg and 0.025 μg/kg in raw milk and milk powder for infants, respectively. In order to protect the consumer's health, control measures should be applied to avoid contamination of feed and foods with aflatoxins.

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“…The supernatants were assayed by HPLC (Moss et al, 1983) for AFBI metabolites. The presence of Tris in the incubation medium resulted in metabolically formed AFBI 8,9-epoxide, being estimated in the form of the highly fluorescent Tris AFBI-8,9-dihydrodiol complex (Neal et al, 1981 (Southern, 1975) to investigate possible viral integration into the host genome.…”

Section: Immuno-blot Assaymentioning

confidence: 99%

The isolation and culture of DHBV-infected embryo and duckling hepatocytes and the effect of aflatoxin B1 or irradiation on these cells

Judah²,

Riley³

et al. 1991

Br J Cancer

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Summary The preparation of primary cultures of control and DHBV-infected duck hepatocytes from embryos and young ducklings is described. Cultures of both embryo and duckling hepatocytes secreted duck serum proteins. Cultures of hepatocytes established from ducklings maintained initial morphology for up to 3 weeks in culture and also exhibited high levels of metabolism of aflatoxin B,. Embryonic cell cultures rapidly lost ability to metabolise AFB, and became overgrown by spindle-shaped cells. Both embryo and duckling cell cultures secreted infective DHBV, and had intracellular replicative forms of the virus. No integration of the virus into the duck genome was observed, and attempts to induce viral integration in the duckling hepatocytes using irradiation and aflatoxin B, toxicity were unsuccessful. The results of the study lend further support to the suggestion that the rarity of liver cancer in DHBV-infected experimental ducks is related to an innate resistance of the hepatocytes to develop DHBV-DNA integration. Another possibility may be related to the lower oncogenic potential of the DHBV strain used for the study. However DHBV infected duckling hepatocytes would appear to offer a suitable material for studying viral replication and mechanisms of aflatoxin B, toxicity during prolonged cell culture.

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The formation of 2,3-dihydroxy-2,3-dihydro-aflatoxin B1 by the metabolism of aflatoxin B1 by liver microsomes isolated from certain avian and mammalian species and the possible role of this metabolite in the acute toxicity of aflatoxin B1

Cited by 76 publications

References 26 publications

Microsomal and cytosolic biotransformation of aflatoxin B1 in four poultry species

Microsomal and cytosolic biotransformation of aflatoxin B1 in four poultry species

Aflatoxins in foods of animal origin

The isolation and culture of DHBV-infected embryo and duckling hepatocytes and the effect of aflatoxin B1 or irradiation on these cells

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