Presence of Mutagens and Carcinogens, Called Aflatoxins, and their Hydroxylated Metabolites in Industrialized Food for Dogs

2018 ◽  
Vol 10 (03) ◽  
Author(s):  
Stephania Fuentes D ◽  
Magda Carvajal M ◽  
Silvia Ruiz V ◽  
Nallely Cecilia Martínez R ◽  
Ariadna Azucena Gomez C ◽  
...  
Keyword(s):  
Hydroxylated Metabolites

PHENOLIC METABOLITES OF DL-NORGESTREL: A METHOD FOR THE REMOVAL OF 1-HYDROXYLATED METABOLITES, POTENTIAL SOURCES OF PHENOLIC ARTIFACTS

1974 ◽  
Vol 76 (4) ◽  
pp. 789-800 ◽  
Author(s):  
Samuel F. Sisenwine ◽  
Ann L. Liu ◽  
Hazel B. Kimmel ◽  
Hans W. Ruelius
Keyword(s):  
Urinary Metabolites ◽  
Ion Exchange Resin ◽  
Gas Chromatography Mass Spectrometry ◽  
Phenolic Metabolites ◽  
Hydroxylated Metabolites ◽  
Analytical Work ◽  
Potential Sources ◽  
Alkaline Conditions ◽  
Artifact Formation ◽  
Work Up

ABSTRACT The identification of 1β-hydroxynorgestrel among the urinary metabolites of dl-norgestrel and the facile transformation of this compound under mild alkaline conditions to a potentially oestrogenic phenol provide an experimental basis for the conclusion advanced by others that the oestrogens present in the urine of subjects treated with synthetic progestens are artifacts formed during analytical work-up. A method has been devised which eliminates 1-hydroxylated metabolites as potential sources of phenolic artifacts. This method is based on the reduction by NaBH4 of the 1-hydroxy-4-en-3-one grouping in the A ring thereby excluding the possibility of aromatization during later fractionation on a basic ion exchange resin that separates neutral from phenolic metabolites. In the urines of women treated with 14C-dl-nogestrel, only 0.17–0.27% of the dose is found to have phenolic properties when this method is used. Two of the phenolic metabolites, 18-homoethynyloestradiol and 16β-hydroxy-18-homoethynyloestradiol, are present in amounts smaller than 0.01 % of the dose. Without the reduction steps the percentages are noticeably higher, indicating artifact formation under alkaline conditions. Similar results were obtained with urines from African Green Monkeys (Cercopithecus Aethiops) that had been dosed with 14C-dl-norgestrel. Radiolabelled 18-homoethynyloestradiol and 16β-hydroxy-18-homoethynyloestradiol were isolated from monkey urine and their identity confirmed by gas chromatography-mass spectrometry.

scholarly journals Stereoselective accumulation of hydroxylated metabolites of amphetamine in rat striatum and hypothalamus

1986 ◽  
Vol 88 (1) ◽  
pp. 285-290 ◽  
Author(s):  
D.F.H. Dougan ◽  
A.M. Duffield ◽  
P.H. Duffield ◽  
D.N. Wade
Keyword(s):  
Rat Striatum ◽  
Hydroxylated Metabolites

scholarly journals Neurosteroid metabolism. 7α-Hydroxylation of dehydroepiandrosterone and pregnenolone by rat brain microsomes

1992 ◽  
Vol 288 (3) ◽  
pp. 959-964 ◽  
Author(s):  
Y Akwa ◽  
R F Morfin ◽  
P Robel ◽  
E E Baulieu
Keyword(s):  
Rat Brain ◽  
Microsomal Protein ◽  
Optimal Conditions ◽  
Hydroxylated Metabolites ◽  
Enzymic Reaction ◽  
Polar Metabolites ◽  
Brain Microsomes ◽  
Prepubertal Rats ◽  
Derivatives Of

Two ‘neurosteroids’, dehydroepiandrosterone (DHEA) and pregnenolone (PREG), are converted by rat brain microsomes into polar metabolites, identified as the respective 7 alpha-hydroxylated (7 alpha-OH) derivatives by the ‘twin ion’ technique of g.l.c.-m.s. with deuterated substrates. The enzymic reaction requires NADPH and is stimulated 2-4-fold by EDTA. Under optimal conditions (pH 7.4, 0.5 mM-NADPH, 1 mM-EDTA), the Km values for DHEA and PREG are 13.8 and 4.4 microM respectively, and the Vmax. values are 322 and 38.8 pmol/min per mg of microsomal protein respectively. Trace amounts of putative 7 beta-OH derivatives of DHEA and PREG are detected. Oestradiol, at a pharmacological concentration of 5 microM, inhibits DHEA and PREG 7 alpha-hydroxylation. Formation of 7 alpha-hydroxylated metabolites is low in prepubertal rats and increases 5-fold in adults. Derivatives of PREG and DHEA, such as PREG sulphate, DHEA sulphate, progesterone and 3 alpha-hydroxy-5 alpha-pregnan-20-one, are known to be neuroactive. Therefore the quantitatively important metabolism to 7 alpha-OH compounds may contribute to the control of neurosteroid activity in brain.

Plasma levels of 7-hydroxymetabolites of dehydroepiandrosterone in healthy Central European aging men

2005 ◽  
Vol 43 (11) ◽  
Author(s):  
Luboslav Stárka ◽  
Richard Hampl ◽  
Miroslav Hanuš ◽  
Michaela Matoušková ◽  
Martin Hill
Keyword(s):  
Human Blood ◽  
Human Life ◽  
Age Groups ◽  
Limited Data ◽  
Age Dependence ◽  
Central European ◽  
Hydroxylated Metabolites ◽  
Aging Men ◽  
One Way Anova ◽  
Hydroxy Metabolite

AbstractEvidence has been accumulating that 7-hydroxyepimers of dehydroepiandrosterone may act as locally active immunomodulatory and immunoprotective agents, counteracting the actions of glucocorticoids. 7α- and 7β-hydroxylated metabolites of dehydroepiandrosterone are present in near nanomolar concentrations in human blood. Limited data have been available on its changes during the last decades of human life. We examined 213 healthy Central European males in age groups from 50 to 91years and determined both 7-hydroxyepimers, 7α- and 7β-hydroxy-dehydroepiandrosterone, in sera using specific radioimmunoassays. The age dependence of steroid levels was evaluated using one-way ANOVA. In men, a distinct decline in 7α-hydroxy-dehydroepiandrosterone with age was observed. The curves for age dependence of 7-hydroxy metabolite levels in males resembled those previously determined for unconjugated dehydroepiandrosterone. The levels of both 7-hydroxylated epimers correlated excellently with each other.

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