Increased retinoic acid metabolism following 3,3′,4,4′,5,5′-hexabromobiphenyl injection

Spear, Philip A.; Garcin, H; Narbonne, Jean‐François

doi:10.1139/y88-194

Cited by 40 publications

(22 citation statements)

References 11 publications

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“…A minor role for CYP1A enzymes in vitamin A oxidation is possible, but the evidence remains equivocal. CYP1A inducers reportedly stimulated ATRA 4-hydroxylation in some [72,73], but not all studies [74]. In other species different CYPs may contribute to the activity.…”

Section: Cyp-dependent 4-hydroxylation Of Atramentioning

confidence: 99%

Altered CYP Expression and Function in Response to Dietary Factors: Potential Roles in Disease Pathogenesis

Murray

2006

CDM

129

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Increasing evidence implicates dietary factors in the progression of diseases, including certain cancers, diabetes and obesity. Diet also regulates the expression and function of CYP genes, which impacts on drug elimination and may also significantly affect disease pathogenesis. Upregulation of CYPs 2E1 and 4A occurs after feeding of experimental diets that are high in fats or carbohydrates; these diets also promote hepatic lipid infiltration, which is a component of the metabolic syndrome that characterises obesity. Increased availability of lipid substrates for CYPs can enhance free radical production and exacerbate tissue injury. Similar processes may also occur in other models of experimental disease states that exhibit a component of altered nutrient utilization. Food-derived chemicals, including constituents of cruciferous vegetables and fruits, modulate CYP expression and the expression of genes that encode cytoprotective phase II enzymes. Certain dietary indoles and flavonoids activate CYP1A expression either by direct ligand interaction with the aryl hydrocarbon receptor (AhR) or by augmenting the interaction of the AhR with xenobiotic response elements in CYP1A1 and other target genes. Other dietary chemicals, including methylenedioxyphenyl (MDP) compounds and isothiocyanates also modulate CYP gene expression. Apart from altered CYP regulation, a number of dietary agents also inhibit CYP enzyme activity, leading to pharmacokinetic interactions with coadministered drugs. A well described example is that of grapefruit juice, which contains psoralens and possibly other chemicals, that inactivate intestinal CYP3A4. Decreased presystemic oxidation by this CYP increases the systemic bioavailability of drug substrates and the likelihood of drug toxicity. Dietary interactions may complicate drug therapy but inhibition of certain CYP reactions may also protect the individual against toxic metabolites and free radicals generated by CYPs. Chemicals in teas and cruciferous vegetables may also inhibit human CYP enzymes that have been implicated in the bioactivation of chemical carcinogens. Thus, food constituents modulate CYP expression and function by a range of mechanisms, with the potential for both deleterious and beneficial outcomes.

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Section: Cyp-dependent 4-hydroxylation Of Atramentioning

confidence: 99%

Altered CYP Expression and Function in Response to Dietary Factors: Potential Roles in Disease Pathogenesis

Murray

2006

CDM

129

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“…Second, the enzymatic reaction system deduced from these studies is also apparently sensitive to the vitamin A status of the animal, because pretreatment in vivo with vitamin A or RA boosted the system for the metabolism of at-RA to polar metabolites, including 4-hydroxyand 4-oxo-RA (46). Later, various CYP450 isozymes purified from human (47), rat (96), and rabbit (87) liver were shown to have significant RA hydroxylation activity in the presence of NADPH, whereas imidazole-based reagents such as ketoconazole were able to reduce the oxidative metabolism of RA in vitro and increase the half-life of RA in vivo (111, 112). Other studies suggested that several cytochrome P450 members including CYP2C8 (47) and CYP3A (55) exhibit RA hydroxylase activity.…”

Section: Introductionmentioning

confidence: 99%

Cytochrome P450s in the Regulation of Cellular Retinoic Acid Metabolism

Ross¹,

2011

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The active metabolite of vitamin A, retinoic acid (RA), is a powerful regulator of gene transcription. RA is also a therapeutic drug. The oxidative metabolism of RA by certain members of the cytochrome P450 (CYP) superfamily helps to maintain tissue RA concentrations within appropriate bounds. The CYP26 family—CYP26A1, CYP26B1, and CYP26C1—is distinguished by being both regulated by and active toward all-trans-RA (at-RA) while being expressed in different tissue-specific patterns. The CYP26A1 gene is regulated by multiple RA response elements. CYP26A1 is essential for embryonic development, whereas CYP26B1 is essential for postnatal survival as well as germ cell development. Enzyme kinetic studies have demonstrated that several CYP proteins are capable of metabolizing at-RA; however, it is likely that CYP26A1 plays a major role in RA clearance. Thus, pharmacological approaches to limiting the activity of CYP26 enzymes may extend the half-life of RA and could be useful clinically in the future.

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“…In a field study on Great Lakes herring gulls (Larus argentatus), liver vitamin A stores were inversely related to the level of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) . Studies with rats have demonstrated that polyhalogenated biphenyl congeners accelerate the conjugation and hydroxylation of retinoic acid in the liver (Spear et al 1988) and bind to transthyretin in rat blood (Brouwer and van den Berg 1986). It is uncertain whether these changes in vitamin A caused by environmental contaminants result in hypo-or hypervitaminosis A or what concomitant physiological effects exist.…”

Section: Introductionmentioning

confidence: 99%

Dove reproduction and retinoid (vitamin A) dynamics in adult females and their eggs following exposure to 3,3′,4,4′-tetrachlorobiphenyl

Spear¹,

Bourbonnais²,

Peakall³

et al. 1989

Can. J. Zool.

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and MOON, T. W. 1989. Dove reproduction and retinoid (vitamin A) dynamics in adult females and their eggs following exposure to 3,3',4,4'-tetrachlorobiphenyl. Can. J. Zool. 67:908-913. One week before mating, ring doves (Streptopelia risoria) received an intraperitoneal injection of vitamin-stripped corn oil containing 0 or 40 pglg 3,3',4,4'-tetrachlorobiphenyl. Of numerous reproductive parameters investigated, egg laying was retarded ( p < 0.001) and 43% of the embryos died primarily between days 4 and 7 of incubation in the exposed group. Exposed females laying viable eggs had higher ( p < 0.01) serum retinol at the time of mating than exposed females producing eggs that failed to develop to hatching. Serum retinol concentrations were greater ( p < 0.05) in exposed males than in control males. A method was developed to extract and quantify five naturally occumng retinoids in egg yolks. When the experiment was repeated, yolk retinol and retinyl palmitate decreased ( p < 0.05) between days 3 and 8 of development in the eggs of the exposed group regardless of embryo viability. No change in yolk retinoids occurred in the control group. At day 3 of incubation, the ratio of retinol: retinyl palmitate in yolks was greater ( p < 0.01) in the viable eggs of the exposed group than in either the controls or the nonviable eggs of the exposed group. Despite the reproductive effects, the repeated dose of biphenyl did not elicit liver porphyrin accumulation or alter internal organ weights. Liver retinol concentrations were lower in males ( p < 0.001) and females ( p < 0.05) exposed to the toxicant than in controls; liver retinyl palmitate was unchanged. These changes in retinoid dynamics during oogenesis and in ovo may be a compensatory response to the toxicant. SPEAR, P. A., BOURBONNAIS, D. H., PEAKALL, D. B., et MOON, T. W. 1989. Dove reproduction and retinoid (vitamin A) dynamics in adult females and their eggs following exposure to 3,3',4,4'-tetrachlorobiphenyl. Can. J. Zool. 67 : 908-913. Une semaine avant d'etre accouplies, des Tourterelles h collier (Streptopelia risoria) ont requ une injection intrapkritoine de 0 ou 40 pglg de 3,3',4,4'-tCtrachlorobiphCnyle. Plusieurs paramktres de la reproduction ont Ct C CtudiCs; chez les oiseaux trait&, la ponte des oeufs a CtC retardCe ( p < 0,001) et 43 % des embryons sont morts principalement entre le 4e et le 7e jours de l'incubation. Au moment de l'accouplement, les femelles traitCes dont les oeufs fkconds se sont dCveloppCs normalement ( N normaux *) avaient un taux de rktinol sCrique supCrieur ( p < 0,Ol) h celui des femelles traitCes dont les oeufs fCconds ne se sont pas dCveloppCs jusqu'h 1'Cclosion ((c anormaux B). Les concentrations de rCtinol sirique Ctaient plus ClevCes chez les miles traitCs ( p < 0,05) que chez les tCmoins. Une mCthode permettant d'extraire et de quantifier cinq ritinoi'des dans les jaunes d'oeufs a Cti mise au point. Lorsque I'expCrience a Ct C rCpCtCe, une diminution ( p < 0,05) des concentrations de rCtinol et de palmitate de rktinol a Ct C enregi...

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Increased retinoic acid metabolism following 3,3′,4,4′,5,5′-hexabromobiphenyl injection

Cited by 40 publications

References 11 publications

Altered CYP Expression and Function in Response to Dietary Factors: Potential Roles in Disease Pathogenesis

Altered CYP Expression and Function in Response to Dietary Factors: Potential Roles in Disease Pathogenesis

Cytochrome P450s in the Regulation of Cellular Retinoic Acid Metabolism

Dove reproduction and retinoid (vitamin A) dynamics in adult females and their eggs following exposure to 3,3′,4,4′-tetrachlorobiphenyl

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