Preventive effect of d-psicose, one of rare ketohexoses, on di-(2-ethylhexyl) phthalate (DEHP)-induced testicular injury in rat

Suna, Shigeru; Yamaguchi, Fuminori; Kimura, Shoji; Tokuda, Masaaki; Jitsunari, Fumihiko

doi:10.1016/j.toxlet.2007.06.015

Cited by 77 publications

(49 citation statements)

References 31 publications

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“…It has 70% relative sweetness but only 0.3% energy of sucrose [1], and is suggested as an ideal sucrose substitute for food products [2]. It has important physiological functions, such as blood glucose suppressive effect [3], [4], reactive oxygen species scavenging activity [5], [6], and neuroprotective effect [7]. In addition, it can improve the gelling behavior and produces good flavor during food process [8], [9].…”

Section: Introductionmentioning

confidence: 99%

Characterization of a Novel Metal-Dependent D-Psicose 3-Epimerase from Clostridium scindens 35704

et al. 2013

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The noncharacterized protein CLOSCI_02528 from Clostridium scindens ATCC 35704 was characterized as D-psicose 3-epimerase. The enzyme showed maximum activity at pH 7.5 and 60°C. The half-life of the enzyme at 50°C was 108 min, suggesting the enzyme was relatively thermostable. It was strictly metal-dependent and required Mn2+ as optimum cofactor for activity. In addition, Mn2+ improved the structural stability during both heat- and urea-induced unfolding. Using circular dichroism measurements, the apparent melting temperature (T m) and the urea midtransition concentration (C m) of metal-free enzyme were 64.4°C and 2.68 M. By comparison, the Mn2+-bound enzyme showed higher T m and C m with 67.3°C and 5.09 M. The Michaelis-Menten constant (K m), turnover number (k cat), and catalytic efficiency (k cat/K m) values for substrate D-psicose were estimated to be 28.3 mM, 1826.8 s−1, and 64.5 mM−1 s−1, respectively. The enzyme could effectively produce D-psicose from D-fructose with the turnover ratio of 28%.

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Section: Introductionmentioning

confidence: 99%

Characterization of a Novel Metal-Dependent D-Psicose 3-Epimerase from Clostridium scindens 35704

et al. 2013

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“…Our microarray analyses revealed that the genes encoding oxidative stress proteins such as glutathione peroxidase 1 (GPX1) and glutathione S-transferase alpha type 4 (GSTA4) were downregulated by MEHP, possibly as a consequence of testosterone inhibition [38]. GPX1 and GSTA are essential for activation of the 17α-hydroxylase and 17,20 lyase activities of the enzyme through electrostatic interactions with their cofactors, principally cytochrome b5 and P450 oxidoreductase (POR) [39].…”

Section: Discussionmentioning

confidence: 98%

Mono-(2-ethylhexyl) Phthalate Directly Alters the Expression of Leydig Cell Genes and CYP17 Lyase Activity in Cultured Rat Fetal Testis

Chauvigné

Plummer²,

Lesné

et al. 2011

PLoS ONE

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Exposure to phthalates in utero alters fetal rat testis gene expression and testosterone production, but much remains to be done to understand the mechanisms underlying the direct action of phthalate within the fetal testis.We aimed to investigate the direct mechanisms of action of mono-(2-ethylhexyl) phthalate (MEHP) on the rat fetal testis, focusing on Leydig cell steroidogenesis in particular.We used an in vitro system based on the culture for three days, with or without MEHP, of rat fetal testes obtained at 14.5 days post-coitum.Exposure to MEHP led to a dose-dependent decrease in testosterone production. Moreover, the production of 5 alpha-dihydrotestosterone (5α-DHT) (−68%) and androstenedione (−54%) was also inhibited by 10 µM MEHP, whereas 17 alpha-hydroxyprogesterone (17α-OHP) production was found to increase (+41%). Testosterone synthesis was rescued by the addition of androstenedione but not by any of the other precursors used. Thus, the hormone data suggested that steroidogenesis was blocked at the level of the 17,20 lyase activity of the P450c17 enzyme (CYP17), converting 17α-OHP to androstenedione. The subsequent gene expression and protein levels supported this hypothesis. In addition to Cyp17a1, microarray analysis showed that several other genes important for testes development were affected by MEHP. These genes included those encoding insulin-like factor 3 (INSL3), which is involved in controlling testicular descent, and Inha, which encodes the alpha subunit of inhibin B.These findings indicate that under in vitro conditions known to support normal differentiation of the fetal rat testis, the exposure to MEHP directly inhibits several important Leydig cell factors involved in testis function and that the Cyp17a1 gene is a specific target to MEHP explaining the MEHP-induced suppression of steroidogenesis observed.

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“…The rare sugar d-psicose is the C-3 epimer of d-fructose, has 70% of relative sweetness but only 0.3% of energy of sucrose [8,9], and has been approved as Generally Regarded as Safe (GRAS) by U.S. Food and Drug Administration (DFA). It has enormous physiological benefits including blood glucose suppressive property [10], neuroprotective effect [11], reactive oxygen species scavenging activity [12], and anti-obesity effect [13,14]. In addition, d-psicose has been considered to be able to improve food quality, for examples, it increases the gelling property and produces higher antioxidant activity and pleasant flavor through Maillard reaction with food proteins [15], and it facilitates melting of the crystalline structure in rice flour upon heating and inhibits re-crystallization during http storage [16].…”

Section: Introductionmentioning

confidence: 99%

Characterization of a d-psicose 3-epimerase from Dorea sp. CAG317 with an acidic pH optimum and a high specific activity

Zhang

et al. 2015

Journal of Molecular Catalysis B: Enzymatic

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Preventive effect of d-psicose, one of rare ketohexoses, on di-(2-ethylhexyl) phthalate (DEHP)-induced testicular injury in rat

Cited by 77 publications

References 31 publications

Characterization of a Novel Metal-Dependent D-Psicose 3-Epimerase from Clostridium scindens 35704

Characterization of a Novel Metal-Dependent D-Psicose 3-Epimerase from Clostridium scindens 35704

Mono-(2-ethylhexyl) Phthalate Directly Alters the Expression of Leydig Cell Genes and CYP17 Lyase Activity in Cultured Rat Fetal Testis

Characterization of a d-psicose 3-epimerase from Dorea sp. CAG317 with an acidic pH optimum and a high specific activity

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