On the biochemical mechanism of tumorigenesis in mouse skin. V. studies of the metabolism of tumor promoting and non promoting phorbol derivatives in vivo and in vitro

Kreibich, Gert; Süß, R.; Kinzel, V.

doi:10.1007/bf00304153

Cited by 26 publications

(3 citation statements)

References 10 publications

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“…Since it has been shown that phorbol esters may be rapidly degraded in some culture systems [8,9], we examined whether degradation as judged by biologic activity also occurred in our neural crest cell cultures. In one series of experiments, TPA and culture medium were replaced every 12 h instead of every 48 h. The results of both protocols, however, were very similar ( Table 3).…”

Section: Effects Of Phorbol Esters On the Differentiation Of Neural Cmentioning

confidence: 99%

Tumor-Promoting Phorbol Esters Promote Melanogenesis and Prevent Expression of the Adrenergic Phenotype in Quail Neural Crest Cells

Sieber‐Blum

Sieber

1981

Differentiation

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Section: Effects Of Phorbol Esters On the Differentiation Of Neural Cmentioning

confidence: 99%

Tumor-Promoting Phorbol Esters Promote Melanogenesis and Prevent Expression of the Adrenergic Phenotype in Quail Neural Crest Cells

Sieber‐Blum

Sieber

1981

Differentiation

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“…The metabolic hydrolysis requires the activity of esterases,the activity of which differs between tissues and species. Kreibich et al (1971Kreibich et al ( , 1974 were the first to disclose that both ester groups of TPA can be hydrolysed in mouse skin and in cultured cells, giving rise to the monoesters 12-tetradecanoylphorbol and phorbol-13-acetate, as well as the product of complete hydrolysis, i.e. phorbol.…”

Section: Laboratory Animalsmentioning

confidence: 99%

Risks for human and animal health related to the presence of phorbol esters in Jatropha kernel meal

2015

EFS2

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Following a request from the European Commission, the risks for human and animal health related to the presence of phorbol esters (PEs) in Jatropha kernel meal were assessed by the EFSA Panel of Contaminants in the Food Chain (CONTAM). Jatropha curcas (Jatropha) seeds contain substantial amounts of extractable oil utilised for biodiesel production. The remaining protein‐rich products (seed meal or kernel meal) may be used as a protein source in animal feed after removal of anti‐nutritive factors and toxic PEs. The available data on absorption of Jatropha PEs after oral ingestion, biotransformation, elimination, and dose‐dependent toxic effects are very limited, and only for pigs a no observed adverse effect level (NOAEL) of 0.4 mg PEs/kg bw per day (12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) equivalent), based on decreases in body weight gain and feed intake, could be identified from short‐term feeding studies. No health based guidance value for humans could be established. Processes that almost completely remove or degrade toxic PEs in Jatropha products are available, resulting in levels below the limit of detection of 3 mg Jatropha PEs/kg (TPA equivalent). Replacement of 50% of the protein in compound feeds with treated Jatropha materials would result in animal exposures that are still 10 to 200‐fold lower than the NOAEL for pigs. The CONTAM Panel concluded that such use of Jatropha material would not pose a health risk to pigs and that the risk to other species is likely to be low. The transfer of Jatropha PEs to animal derived products is unknown. In a human exposure scenario using a 50% transfer rate from feed to milk, a daily intake of 1 μg Jatropa PEs/kg bw per day was calculated. The CONTAM Panel concluded that more data are needed to draw firm conclusions on human risks.

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“…Zur Analyse der Phorbolester wurden bisher, neben biologischen Testen [4], hauptsachlich DC-Ver-Tell der Dissertation in Vorbereitung fahren [7,8,9] verwendet. Diese sind allerdings nicht ausreichend, um hiermit gleichzeitig auch genaue Zuordnungen und Identifizierungen durchzufuhren [7].…”

Section: Introductionunclassified

HPLC-Nachweis und Isolierung von Phorbolestern aus Crotonöl

Bauer¹,

Tittel²,

Wagner³

1983

Planta Med

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A HPLC method using reversed-phase columns is described for the determination and isolation of phorbolesters in crotonoil. The identification of the compounds is based on an off-line combination of HPLC-MS, as well as on fatty acid analysis by GC. With this method several new phorbolesters of crotonoil could be detected. This method is also suitable for the determination of phorbol- or similar diterpenesters in other Euphorbiaceae.

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On the biochemical mechanism of tumorigenesis in mouse skin. V. studies of the metabolism of tumor promoting and non promoting phorbol derivatives in vivo and in vitro

Cited by 26 publications

References 10 publications

Tumor-Promoting Phorbol Esters Promote Melanogenesis and Prevent Expression of the Adrenergic Phenotype in Quail Neural Crest Cells

Tumor-Promoting Phorbol Esters Promote Melanogenesis and Prevent Expression of the Adrenergic Phenotype in Quail Neural Crest Cells

Risks for human and animal health related to the presence of phorbol esters in Jatropha kernel meal

HPLC-Nachweis und Isolierung von Phorbolestern aus Crotonöl

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