Androgen concentrations in umbilical cord blood and their association with maternal, fetal and obstetric factors.

The aim of this study was to measure umbilical blood androgen concentrations in a birth cohort using a highly specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay and assesses the effects of sex, labor, and gestational age on fetal androgen levels at birth. We performed a prospective cohort study of androgen concentrations in mixed arterial and venous umbilical cord serum from 803 unselected singleton pregnancies from a general obstetric population in Western Australia. Total testosterone (TT), Δ4-androstenedione, and dehydroepiandrosterone were extracted from archived cord serum samples and measured using LC-MS/MS. SHBG was measured by ELISA; free testosterone (FT) and bioavailable testosterone (BioT) values were also calculated. Median values for all three androgens were generally lower than previously published values. Levels of TT, FT, BioT, and SHBG were significantly higher in male verses female neonates (P<0.0001), while dehydroepiandrosterone levels were higher in females (P<0.0001). Labor was associated with a significant (∼15-26%) decrease in median cord blood TT and FT levels (both sexes combined), but a modest (∼16-31%) increase in SHBG, Δ4-androstenedione, and dehydroepiandrosterone concentrations. TT and FT were significantly negatively correlated with gestational age at delivery, while SHBG, Δ4-androstenedione, and dehydroepiandrosterone were positively correlated. Antenatal glucocorticoid administration also had a significant effect in the multiple regression models. This is the first study to report umbilical cord androgen levels in a large unselected population of neonates using LC-MS/MS. Our findings suggest that previous studies have over-estimated cord androgen levels, and that fetal, maternal, and obstetric factors influence cord androgen levels differentially. Caution should be exercised when interpreting previously-published data that have not taken all of these factors into account.

Simultaneous determination of oleuropein and hydroxytyrosol in rat plasma using liquid chromatography with fluorescence detection.

Oleuropein, the main glycoside present in olives, and hydroxytyrosol, the principal degradation product of oleuropein present in olive oil, have been linked to reduction of coronary heart disease and certain cancers. In the present study a direct and sensitive reversed-phase high-performance liquid chromatographic assay was developed for simultaneous quantification of both oleuropein and hydroxytyrosol. The plasma protein was precipitated with acetonitrile, samples were then centrifuged and supernatants were dried, and reconstituted with water prior to injection. The chromatographic analysis was carried out using a phenyl column and an isocratic elution of acidified water and acetonitrile with fluorescence detection at 281 and 316 nm for excitation and emission, respectively. The calibration curve was linear and limits of quantification were 30 ng/ml and 3 microg/ml for hydroxytyrosol and oleuropein, respectively. The method has been successfully applied to monitor oleuropein and hydroxytyrosol plasma levels in the rat.

Inhibition of CYP3A-mediated oxidation in human hepatic microsomes by the dietary derived complex phenol, gallic acid.

Plant polyphenols, such as gallic acid, have been reported to have a range of biological activities including antimutagenic effects. Previously, we reported that gallic acid (3,4,5-trihydroxybenzoic acid), an agent found in wine and tea, inhibits androstenedione 6beta-hydroxylase activity (Ki 70 microm), a cytochrome P450 (CYP3A) marker in human liver microsomes. The pre-incubation of gallic acid (100 microM) with human liver microsomes in the absence of NADPH, as compared with the presence of NADPH, before assay of androstenedione 6beta-hydroxylase activity significantly increased the inhibitory effects of the gallic acid (0.03 +/- 0.03 nmol (mg microsomal protein)(-1) min(-1) compared with 0.20 +/- 0.06 nmol (mg microsomal protein) (-1) min(-1) (P < 0.05)). The antioxidant ascorbic acid and the radical scavenger glutathione prevented this observed increase in inhibition. Removal of gallic acid-derived products from the incubation completely restored CYP3A activity. In contrast, the activities of CYP1A and CYP2E, and non-CYP mediated reductive microsomal 17beta-hydroxysteroid dehydrogenase activity were refractory to inhibition by gallic acid.