Retinoid metabolism (LRAT, REH) in the yolk-sac membrane of Japanese quail eggs and effects of mono-ortho-PCBs

Boily, Monique; Ndayibagira, Aristocle; Spear, Philip A.

doi:10.1016/s1532-0456(02)00146-1

Cited by 12 publications

(9 citation statements)

References 46 publications

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“…Quail received three i.p. injections of PCB‐77 (5 mg/kg) and showed no overt toxicity (Boily et al., ,b). Eggs were collected but there was no apparent embryo toxicity.…”

Section: Assessmentmentioning

confidence: 99%

Risk for animal and human health related to the presence of dioxins and dioxin‐like PCBs in feed and food

Knutsen¹,

Alexander²,

Barregård³

et al. 2018

EFS2

137

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The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of dioxins (PCDD/Fs) and DL‐PCBs in feed and food. The data from experimental animal and epidemiological studies were reviewed and it was decided to base the human risk assessment on effects observed in humans and to use animal data as supportive evidence. The critical effect was on semen quality, following pre‐ and postnatal exposure. The critical study showed a NOAEL of 7.0 pg WHO2005‐TEQ/g fat in blood sampled at age 9 years based on PCDD/F‐TEQs. No association was observed when including DL‐PCB‐TEQs. Using toxicokinetic modelling and taking into account the exposure from breastfeeding and a twofold higher intake during childhood, it was estimated that daily exposure in adolescents and adults should be below 0.25 pg TEQ/kg bw/day. The CONTAM Panel established a TWI of 2 pg TEQ/kg bw/week. With occurrence and consumption data from European countries, the mean and P95 intake of total TEQ by Adolescents, Adults, Elderly and Very Elderly varied between, respectively, 2.1 to 10.5, and 5.3 to 30.4 pg TEQ/kg bw/week, implying a considerable exceedance of the TWI. Toddlers and Other Children showed a higher exposure than older age groups, but this was accounted for when deriving the TWI. Exposure to PCDD/F‐TEQ only was on average 2.4‐ and 2.7‐fold lower for mean and P95 exposure than for total TEQ. PCDD/Fs and DL‐PCBs are transferred to milk and eggs, and accumulate in fatty tissues and liver. Transfer rates and bioconcentration factors were identified for various species. The CONTAM Panel was not able to identify reference values in most farm and companion animals with the exception of NOAELs for mink, chicken and some fish species. The estimated exposure from feed for these species does not imply a risk.

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“…Quail received three i.p. injections of PCB‐77 (5 mg/kg) and showed no overt toxicity (Boily et al., ,b). Eggs were collected but there was no apparent embryo toxicity.…”

Section: Assessmentmentioning

confidence: 99%

Risk for animal and human health related to the presence of dioxins and dioxin‐like PCBs in feed and food

Knutsen¹,

Alexander²,

Barregård³

et al. 2018

EFS2

137

View full text Add to dashboard Cite

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“…For lipophilic compounds such as PCBs vehicles can be divided into 3 categories: organic solvents such as DMSO (dimethyl sulfoxide) and triolein, plant oils such as corn and safflower oils, and emulsions. 12,19,[36][37][38][39][40][41][42][43][44][45][46] While only microliter volumes of organic solvents are used as egg injection vehicles, the possibility remains that while they may not alter overall toxicity, they may disrupt other physiological processes within the developing embryo. The same can be suggested of the plant oils.…”

Section: Introductionmentioning

confidence: 99%

Comparison of vehicle mortality followingin ovoexposure of Japanese quail (Coturnix japonica) eggs to corn oil, triolein and a fatty acid mix

Dean

Baltos

Carro

et al. 2016

Endocrine Disruptors

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The use of avian egg bioassays for the determination of embryonic mortality and development effects of toxicant exposure is widespread in ecotoxicology. While these studies have a number of experimental limitations to consider, they offer a rapid, cost effective alternative to maternal feeding studies. In preparing to conduct such studies a number of factors must be taken into consideration, including solubility of the toxicant, dissolution solvent, injection site, volume and incubation position. Species-specific requirements for humidity and position should be considered in order to optimize successful incubation with different species. Japanese quail eggs, were injected prior to incubation with 1ml or 5ml of corn oil, triolein or a fatty acid mix, using air cell or albumen injection. Eggs were incubated according to standard poultry practices or in a prone position to determine if there were any differences in hatching success. Hatching success was reduced in eggs that were injected with 5ml and those incubated in a prone position. The highest rate of hatching success was observed for eggs injected with 1ml of the fatty acid mixture through the air cell.

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“…Dietary carotenoids are cleaved to retinal, symmetrically or asymmetrically, by the enzymes ␤,␤-carotene-15,15=-monooxygenase (BCMO1) and ␤,␤-carotene-9=,10=-dioxygenase (BCDO2), respectively (41,80). Within the intestinal lumen, dietary REs are enzymatically hydrolyzed to retinol in a hydrolase esterification process by two main enzyme activities: retinyl ester hydrolase (REH) and lecithin: retinol acyltransferase (LRAT) (7,9,76). Most of the REs formed in the intestine are incorporated into chylomicrons [CMs (26)], secreted into the intestinal lymph (7,8,76), and directed into the general circulation.…”

mentioning

confidence: 99%

Insight into molecular pathways of retinal metabolism, associated with vitellogenesis in zebrafish

Levi

Ziv

Admon

et al. 2012

American Journal of Physiology-Endocrinology and Metabolism

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Levi L, Ziv T, Admon A, Levavi-Sivan B, Lubzens E. Insight into molecular pathways of retinal metabolism, associated with vitellogenesis in zebrafish. Am J Physiol Endocrinol Metab 302: E626 -E644, 2012. First published December 28, 2011; doi:10.1152/ajpendo.00310.2011Retinal is the main retinoid stored in oviparous eggs of fish, amphibians, and reptiles, reaching the oocytes in association with vitellogenins, the yolk precursor proteins. During early presegmentation stages of zebrafish embryos, retinal is metabolized to retinoic acid (RA), which regulates genes involved in cell proliferation, differentiation, and tissue function and is therefore essential for normal embryonic development. While synthesis of vitellogenin and its regulation by 17␤-estradiol (E2) were extensively investigated, pathways for retinal synthesis remain obscure. We determined the expression pattern of 46 candidate genes, aiming at identifying enzymes associated with retinal synthesis, ascertaining whether they were regulated by E2, and finding pathways that could fulfill the demand for retinoids during vitellogenesis. Genes associated with retinal synthesis were upregulated in liver (rdh10, rdh13, sdr) and surprisingly also in intestine (rdh13) and ovary (rdh1, sdr), concomitantly with higher gene expression and synthesis of vitellogenins in liver but also in extrahepatic tissues, shown here for the first time. Vitellogenin synthesis in the ovary was regulated by E 2. Gene expression studies suggest that elevated retinal synthesis in liver, intestine, and ovary also depends on cleavage of carotenoids (by Bcdo2 or Bmco1), but in the ovary it may also be contingent on higher uptake of retinol from the circulatory system (via Stra6) and retinol synthesis from retinyl esters (by Lpl). Decrease in oxidation (by Raldh2 or Raldh3) of retinal to RA and/or degradation of RA (by Cyp26a1) may also facilitate higher hepatic retinal levels. Together, these processes enable meeting the putative demands of retinal for binding to vitellogenins. Bioinformatic tools reveal multiple hormone response elements in the studied genes, suggesting complex and intricate regulation of these processes. extrahepatic vitellogenin synthesis; regulatory response elements; retinoids; carotenoids RETINAL IS THE PREDOMINANT RETINOID in eggs and oocytes of marine fish and some freshwater fish species and may constitute almost the entire pool of retinoids in these eggs. In oviparous eggs of nonmammalian vertebrates such as teleosts, amphibians, and birds, maternally derived retinal is bound via a Schiff-base linkage to vitellogenins (Vtgs) (15, 32, 62, 63, 64, 72 reviewed in 50). The retinal in fish oocytes and eggs consists of several isomers, whereas the all-trans form is the most abundant in zebrafish embryos (15,44). The use of the all-trans isomer of retinal for major retinoid storage is unique to reptiles, anamniotic vertebrates (teleosts and amphibians), and eggs of ascidian (33,34). This is in contrast to higher vertebrates (birds and mammals), where retinol is the...

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Retinoid metabolism (LRAT, REH) in the yolk-sac membrane of Japanese quail eggs and effects of mono-ortho-PCBs

Cited by 12 publications

References 46 publications

Risk for animal and human health related to the presence of dioxins and dioxin‐like PCBs in feed and food

Risk for animal and human health related to the presence of dioxins and dioxin‐like PCBs in feed and food

Comparison of vehicle mortality followingin ovoexposure of Japanese quail (Coturnix japonica) eggs to corn oil, triolein and a fatty acid mix

Insight into molecular pathways of retinal metabolism, associated with vitellogenesis in zebrafish

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