Liquid chromatographic determination of urinary 6β-hydroxycortisol to assess cytochrome p-450 3A activity in HIV positive pregnant women

Homma, Masato; Beckerman, Karen; Hayashi, Sandra; Jayewardene, Anura L.; Oka, Kitaro; Gambertoglio, John G.; Aweeka, Francesca

doi:10.1016/s0731-7085(00)00334-4

Cited by 25 publications

(14 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A recently published well-designed clinical study clearly shows that CYP3A activity, as measured by N-demethylation of dextromethorphan, is increased approximately 35% throughput all trimesters of pregnancy [159], confirming previous more limited investigations of cortisol [160], nifedipine [161], and nelfinavir/indinavir [162] metabolism during pregnancy, suggesting that hormonal changes may influence CYP3A expression. However, hormonal changes during the menstrual cycle have generally not been shown to affect CYP3A expression.…”

Section: Steroid Hormonessupporting

confidence: 76%

Evolution and Function of the NR1I Nuclear Hormone Receptor Subfamily (VDR, PXR, and CAR) with Respect to Metabolism of Xenobiotics and Endogenous Compounds

Reschly¹,

Krasowski²

2006

CDM

126

130

View full text Add to dashboard Cite

The NR1I subfamily of nuclear hormone receptors includes the 1,25-(OH) 2 -vitamin D 3 receptor (VDR; NR1I1), pregnane X receptor (PXR; NR1I2), and constitutive androstane receptor (CAR; NR1I3). PXR and VDR are found in diverse vertebrates from fish to mammals while CAR is restricted to mammals. Current evidence suggests that the CAR gene arose from a duplication of an ancestral PXR gene, and that PXR and VDR arose from duplication of an ancestral gene, represented now by a single gene in the invertebrate Ciona intestinalis. Aside from the high-affinity effects of 1,25-(OH) 2 -vitamin D 3 on VDRs, the NR1I subfamily members are functionally united by the ability to bind potentially toxic endogenous compounds with low affinity and initiate changes in gene expression that lead to enhanced metabolism and elimination (e.g., induction of cytochrome P450 3A4 expression in humans). The detoxification role of VDR seems limited to sensing high concentrations of certain toxic bile salts, such as lithocholic acid, whereas PXR and CAR have the ability to recognize structurally diverse compounds. PXR and CAR show the highest degree of crossspecies variation in the ligand-binding domain of the entire vertebrate nuclear hormone receptor superfamily, suggesting adaptation to species-specific ligands. This review examines the insights that phylogenetic and experimental studies provide into the function of VDR, PXR, and CAR, and how the functions of these receptors have expanded to evolutionary advantage in humans and other animals.

show abstract

Section: Steroid Hormonessupporting

confidence: 76%

Evolution and Function of the NR1I Nuclear Hormone Receptor Subfamily (VDR, PXR, and CAR) with Respect to Metabolism of Xenobiotics and Endogenous Compounds

Reschly¹,

Krasowski²

2006

CDM

126

130

View full text Add to dashboard Cite

show abstract

“…However, nevirapine administered for 14 days significantly increased the median erythromycin breath test by 22% [11], and delavirdine decreased by 70-75% the predose erythromycin breath test values after both short-and long-term administration [12]. In a fourth study, urinary 6b-hydroxycortisol measured in HIV-positive pregnant women was comparable to that determined in the urine of healthy subjects, although the patients were all treated with PIs such as indinavir and nelfinavir [13], which are CYP3A inhibitors [4]. Finally, efavirenz significantly increased the mean erythromycin breath test result in a dose-and time-dependent manner (55% mean induction at 400 mg and 33% induction at 200 mg) in two groups of 12 healthy subjects receiving 200 mg/day or 400 mg/day for 10 days [14].…”

Section: Introductionmentioning

confidence: 83%

“…Some hypotheses have been put forward to tentatively explain these mixed results [10][11][12][13][14]. Multiple CYP isozymes play a role in the metabolism of dapsone, and it is not clear whether CYP3A is the sole metabolic pathway for the 6b-hydroxylation of cortisol [10].…”

Section: Introductionmentioning

confidence: 99%

Variations of CYP3A activity induced by antiretroviral treatment in HIV-1 infected patients

Fellay

Marzolini

Décosterd

et al. 2005

Eur J Clin Pharmacol

View full text Add to dashboard Cite

show abstract

“…While the use of UV detection is simpler and cheaper to operate, it requires the use of solid-phase extraction (SPE) to remove interferences and to reach suitable detection levels. This is achieved by using a highly specific phenyl boronic acid (PBA) extraction column that exclusively extracts poly-ol species via interaction with surfacebound borate groups [2,9,10]. Due to the extremely polar nature of ribavirin, analytical separations are performed on a C 18 column in aqueous or near aqueous conditions (, 5% organic solvent), which can be detrimental to many analytical columns, while strongly retained analytes are removed by cleaning overnight with a mobile phase containing a high amount of organic solvent [2,9].…”

Section: Introductionmentioning

confidence: 99%

Determination of ribavirin in human serum and plasma by capillary electrophoresis

2004

View full text Add to dashboard Cite

The electrophoretic separation of ribavirin and 5-methylcytidine (internal standard) by capillary electrophoresis was examined. Separation was achieved using reverse polarity in a 100 mM borate electrolyte, pH 9.1, with 5 mM spermine added to reduce the electroosmotic flow. Sample preparation based on acetonitrile protein precipitation was found to be unsuitable for ribavirin analysis in patient samples due to insufficient sensitivity and interferences. Solid-phase extraction employing phenyl boronic acid cartridges provided cleaner separations. Using this approach with 500 microL sample and reconstitution of the dried extract into 100 microL of 33% v/v 100 mM phosphate buffer, pH 6.4 / 67% v/v acetonitrile, the detection and quantitation limits were determined to be 0.05 and 0.10 microg/mL, respectively, a sensitivity that is suitable for therapeutic drug monitoring of ribavirin in human plasma and serum samples. The method was validated and compared to a high-performance liquid chromatography (HPLC) method, showing excellent agreement between the two for a set of samples that stemmed from patients being treated with ribavirin and interferon-alpha-2b for a hepatitis C virus infection.

show abstract

Liquid chromatographic determination of urinary 6β-hydroxycortisol to assess cytochrome p-450 3A activity in HIV positive pregnant women

Cited by 25 publications

References 14 publications

Evolution and Function of the NR1I Nuclear Hormone Receptor Subfamily (VDR, PXR, and CAR) with Respect to Metabolism of Xenobiotics and Endogenous Compounds

Evolution and Function of the NR1I Nuclear Hormone Receptor Subfamily (VDR, PXR, and CAR) with Respect to Metabolism of Xenobiotics and Endogenous Compounds

Variations of CYP3A activity induced by antiretroviral treatment in HIV-1 infected patients

Determination of ribavirin in human serum and plasma by capillary electrophoresis

Contact Info

Product

Resources

About