Analysis of estrogens and androgens in postmenopausal serum and plasma by liquid chromatography–mass spectrometry

Abstract

Liquid chromatography-selected reaction monitoring/mass spectrometry-based methodology has evolved to the point where accurate analyses of trace levels of estrogens and androgens in postmenopausal serum and plasma can be accomplished with high precision and accuracy. A suite of derivatization procedures has been developed, which together with modern mass spectrometry instrumentation provide investigators with robust and sensitive methodology. Preionized derivatives are proving to be useful as they are not subject to suppression of the electrospray signal. Postmenopausal women with elevated plasma or serum estrogens are thought to be at increased risk for breast and endometrial cancer. Therefore, significant advances in risk assessment should be possible now that reliable methodology is available. It is also possible to conduct analyses of multiple estrogens in plasma or serum. Laboratories that are currently employing liquid chromatography/mass spectrometry methodology can now readily implement this strategy. This will help conserve important plasma and serum samples available in Biobanks, as it will be possible to conduct high sensitivity analyses using low initial sample volumes. Reported levels of both conjugated and non-conjugated estrogen metabolites are close to the limits of sensitivity of many assays to date, urging caution in the interpretation of these low values. The analysis of serum androgen precursors in postmenopausal women has not been conducted routinely in the past using liquid chromatography/mass spectrometry methodology. Integration of serum androgen levels into the panel of metabolites analyzed could provide additional information for assessing cancer risk and should be included in the future.

Insulin resistance in an animal model of polycystic ovary disease is aggravated by vitamin D deficiency: Vascular consequences

“…All calibrators were treated in the same way as test samples. 17,18 Serum ratio of testosterone to DHT ratio was calculated. Leptin levels were measured at eighth week of treatment with ELISA (Phoenix Pharmaceuticals/Phoenix Europe GmbH, Germany).…”

What are The Main Considerations for Bioanalysis of Estrogens and Androgens in Plasma and Serum Samples from Postmenopausal Women?

“…[14] showed that the Helix pomatia enzyme, which has both a β-glucuronidase + arylsulfatase activity, and is used quite extensively for the androgen analysis, is contaminated with 3β-hydroxysteroid dehydrogenase activity which can transform dehydroepiandrosterone into 5α-androstene-3,17-dione (AD). Considering that the levels of dehydroepiandrosterone are in the low ng/ml range [1] and the AD levels are about two orders of magnitude lower [1], even low 3β-hydroxysteroid dehydrogenase activity could lead to elevated levels of AD.…”

“…Other circulating forms of estrogens in postmenopausal women include methyl ether metabolites as well as β-glucuronide and sulfate conjugates. However, only the sulfate conjugates can serve as precursors (through the action of sulfatases) of the corresponding unconjugated estrogens in tissues [1]. Estradiol (E2) is one of the essential sex hormones that are required for reproduction in premenopausal women.…”

“…Reported values for circulating E2 have a mean value of 7.3 pg/ml [1,6]. E1 measurements are not particularly challenging since its concentration is higher, but all the other metabolites are at the same levels as E2 or lower.…”

Ultra-high sensitivity analysis of estrogens for special populations in serum and plasma by liquid chromatography–mass spectrometry: Assay considerations and suggested practices

“…These assays afford good sensitivity, but often lack specificity due to the cross-reaction of the antibodies used in the assays with other steroids. The inter-laboratory variability of immunoassays has caused significant problems when interpreting epidemiologic studies [4, 6]. Another limitation of immunoassay-based methods is the reliance on single analyte-by-analyte measurement, thus multiple assays are required to measure all the metabolites from a single estrogen [7].…”