Induction of Hepatic Cytochrome P-450 by Phenobarbital in Semi-aquatic Frog (Rana pipiens)

Khan, M. A. Q.; Qadri, Syed Yamin; Tomar, Supriya; Fish, D. N.; Gururajan, Lavanya; Poria, Mahipal S.

doi:10.1006/bbrc.1998.8281

Cited by 10 publications

(7 citation statements)

References 45 publications

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“…7-Ethoxyresorufin O-deethylase (EROD) activity in the hepatic microsomes of R. pipiens more than doubled following injection of BNF, and such an induction by PB was observed for AE, EROD, and 7-pentoxyresorufin O-depentylase. 62) These results showed the presence of CYP1A and 2B in this frog. The induction of hepatic CYP1A (53.5 kDa) in R. pipiens by 3,3′,4,4′,5-pentachlorobiphenyl (PCB126) was confirmed by using monoclonal antibody 1-12-3 in the Western blot analysis.…”

Section: Relevant Enzymesmentioning

confidence: 58%

“…59,60) Its content also increased with development from tadpole to adult by a factor of 2 to 4 in X. laevis 61) and R. pipiens. 62) The optimal pH and temperature for CYP activity are generally 7.4 to 7.5 and around 25°C, but a higher temperature up to 37°C was known for aminopyrine N-demethylase (AD) in R. pipiens. 63) The hydroxylation of biphenyl and coumarin was reported for adult R. temporaria by using the liver post-mitochondrial supernatant, and either the requirement of NADPH as a cofactor or the reduced activity by a typical CYP inhibitor, SKF-525A, strongly suggested the involvement of CYP.…”

Section: Relevant Enzymesmentioning

confidence: 99%

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Bioconcentration and metabolism of pesticides and industrial chemicals in the frog

Katagi

Ose

2014

J. Pestic. Sci.

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Exposure to pesticide residues is claimed to be one of the possible causes of frog decline. Knowledge of basic information on the uptake, metabolism and depuration processes of pesticides in the frog is needed to understand the relationship between exposure and toxic effects from their actual body burden, together with their bioconcentration. The hydrophobicity of pesticides and industrial chemicals was one of the most important factors controlling bioconcentration, similarly to fish, when frogs are exposed to contaminated water. Skin absorption was also a key route in the uptake process especially in the adult frog. The metabolic profiles in the frog, mainly examined by an intraperitoneal injection technique, were common to other aquatic species without any frog-specific transformation reaction. The effects of developmental stage, sex, species and environmental factors such as temperature were observed for bioconcentration and metabolism.

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Section: Relevant Enzymesmentioning

confidence: 58%

Section: Relevant Enzymesmentioning

confidence: 99%

Bioconcentration and metabolism of pesticides and industrial chemicals in the frog

Katagi

Ose

2014

J. Pestic. Sci.

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“…In contrast, induction of hepatic CYP2B by phenobarbital (PB) has been reported in semi-aquatic frog (Rana pipiens). 30) Therefore, the determinations of EROD and PROD activities in frog are important markers of toxicological research. 30) Hanioka et al 9,10) reported that BROD and PROD activities in rats, were induced by all doses of TCS, suggesting that TCS induced the hepatic P450 isoforms of the CYP2B subfamily.…”

Section: Resultsmentioning

confidence: 99%

“…30) Therefore, the determinations of EROD and PROD activities in frog are important markers of toxicological research. 30) Hanioka et al 9,10) reported that BROD and PROD activities in rats, were induced by all doses of TCS, suggesting that TCS induced the hepatic P450 isoforms of the CYP2B subfamily. We also assessed the induction of EROD and PROD activities in hepatic microsomes from male frog exposed to TCS but found no difference between the EROD and PROD activities among the TCS treatment groups (Fig.…”

Section: Resultsmentioning

confidence: 99%

Effects of Nonylphenol and Triclosan on Production of Plasma Vitellogenin and Testosterone in Male South African Clawed Frogs (Xenopus laevis)

Matsumura

Ishibashi

Hirano

et al. 2005

Biological & Pharmaceutical Bulletin

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Recently, a number of studies have been performed worldwide to examine endocrine-disrupting chemicals (EDCs) and their interactions with the development and function of various systems in animals and humans.1-3) Among these EDCs, alkylphenol polyethoxylate non-ionic surfactants are used in the manufacture of cleaning agents, cosmetics and food products, as well as in plastic polymerization processes. Nonylphenol ethoxylates have predominantly been used, amounting to about 80% of the production of alkylphenol surfactants. In a recent study, nonylphenol (NP) had significant effects on the reproductive potential of medaka (Oryzias latipes) at concentrations as low as 17.7 mg/l, 4) and 50% of the male fish in the 50 mg/l treatment and 86% of the males in the 100 mg/l treatment developed testis-ova, an intersex condition characterized by both testicular and ovarian tissue in the gonad. 5) On the other hand, triclosan (TCS, 2,4,4Ј-trichloro-2Ј-hydroxydiphenyl ether) is widely used as an antibacterial agent in liquid toothpaste, soap, shampoo, and cosmetics, and is frequency found in wastewater effluent. Water samples collected near the outfall of a wastewater treatment plant in Rhode Island, U.S.A., showed 10-20 mg/l of TCS in the effluent and 80-100 mg/g of TCS in the sediment.6,7) Our previous study suggests that TCS has high toxicity on the early life stages of medaka, and that the metabolite of TCS may be a weak estrogenic compound in male medaka but with no adverse effect on reproductive success (such as fecundity and fertility) and offspring. 8) Moreover, Hanioka et al. 9,10) reported that 7-benzyloxyresorufin Odebenzylase (BROD) and 7-pentoxyresorufin O-depentylase (PROD) activities, which are associated with CYP2B1 activity, were remarkably induced by all doses of TCS in rats. Their results suggested that TCS induces the P450 isoforms of the CYP2B subfamily in the rat liver, and that the induced P450 isozymes were closely related to the toxicity of TCS or its chlorinated derivatives. However, there is no information about the effects of these chemicals on the hormonally responses of amphibian. 11)The South African clawed frog (Xenopus laevis) is sensitive to environmental chemicals as it spends all the life stages (egg, larva, and adulthood) in water. Hayes et al. 12) examined the effects of atrazine on sexual development in X. laevis, and reported that atrazine (Ͼ or ϭ0.1 mg/l) induced hermaphroditism and demasculinized the larynx of exposed males (Ͼ or ϭ1.0 mg/l), and male X. laevis suffered a 10-fold decrease in testosterone levels when exposed to 25 mg/l atrazine. Therefore, in the present study, we used X. laevis as a test organism, and investigated the effects of NP and TCS on production of plasma vitellogenin (Vg, egg yolk protein precursor), steroid hormone testosterone (T) synthesis, and hepatic CYP1A and CYP2B, as measured by the ethoxyresorufin O-deethylase (EROD) or PROD activities in male X. laevis. To our knowledge, this is first study on the effect of TCS in male X. laevis. MATERIALS AND MET...

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“…However, a subset of the responsible enzymes, glucuronidases (UGTs), can reduce circulating levels of THs through biliary elimination as in mammals. Regarding phase I species, hepatic microsomal cytochrome P450 2B1 was found to be induced by pentobarbital in adults of the semiaquatic frog, Rana pipiens , but not in frog tadpoles and adults of the aquatic frog Xenopus laevis 4 . Deiodinase enzymes, type 2 and 3 iodothyronine deiodinase, are found in several peripheral target tissues in amphibians, and the level of expression is closely connected with metamorphosis 5,6 .…”

Section: Thyroid Hormones and Their Related Effectorsmentioning

confidence: 99%

Thyroid Hormone-disrupting Effects and the Amphibian Metamorphosis Assay

2012

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There are continued concerns about endocrine-disrupting chemical effects, and appropriate vertebrate models for assessment of risk are a high priority. Frog tadpoles are very sensitive to environmental substances because of their habitat and the complex processes of metamorphosis regulated by the endocrine system, mainly thyroid hormones. During metamorphosis, marked alteration in hormonal factors occurs, as well as dramatic structural and functional changes in larval tissues. There are a variety of mechanisms determining thyroid hormone balance or disruption directly or indirectly. Direct-acting agents can cause changes in thyroxine synthesis and/or secretion in thyroid through effects on peroxidases, thyroidal iodide uptake, deiodinase, and proteolysis. At the same time, indirect action may result from biochemical processes such as sulfation, deiodination and glucuronidation. Because their potential to disrupt thyroid hormones has been identified as an important consideration for the regulation of chemicals, the OECD and the EPA have each established guidelines that make use of larval African clawed frogs (Xenopus laevis) and frog metamorphosis for screening and testing of potential endocrine disrupters. The guidelines are based on evaluation of alteration in the hypothalamic-pituitary-thyroid axis. One of the primary endpoints is thyroid gland histopathology. Others are mortality, developmental stage, hind limb length, snout-vent length and wet body weight. Regarding histopathological features, the guidelines include core criteria and additional qualitative parameters along with grading. Taking into account the difficulties in evaluating amphibian thyroid glands, which change continuously throughout metamorphosis, histopathological examination has been shown to be a very sensitive approach.

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Induction of Hepatic Cytochrome P-450 by Phenobarbital in Semi-aquatic Frog (Rana pipiens)

Cited by 10 publications

References 45 publications

Bioconcentration and metabolism of pesticides and industrial chemicals in the frog

Bioconcentration and metabolism of pesticides and industrial chemicals in the frog

Effects of Nonylphenol and Triclosan on Production of Plasma Vitellogenin and Testosterone in Male South African Clawed Frogs (Xenopus laevis)

Thyroid Hormone-disrupting Effects and the Amphibian Metamorphosis Assay

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