A reliable method for the determination of urinary estriol in pregnancy

A reliable method for the estimation of urinary estriol in pregnancy is presented. This method is based upon acid hydrolysis, solvent partition, methylation and chromatography. Estriol is measured by colorimetry using the Kober reaction. All results are corrected for procedural loss by adding tritium-labelled estriol-16-glucosiduronate to the unhydrolyzed urine.This method proves to be sufficiently specific, accurate and precise. One operator may complete six assays within one working day.It is emphasized that a comprehensive recovery control which includes the initial hydrolytic procedure is essential if estriol determinations are to serve as a diagnostic aid in obstetrics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33013/1/0000397.pd

The use of silica gel impregnated glass fiber sheets in plasma estriol assays

The fluorimetric quantitation of nanogram amounts of estriol extracted from plasma is sometimes impaired by impurities which interfere with fluorescence. Instant thin-layer chromatography on silica gel impregnated glass fiber sheets (ITLC-SG) removes such impurities originating from extracts as well as from solvents used in the course of analysis. This convenient, rapid and effective chromatographic procedure does not introduce interfering substances by itself. With the utilization of ITLC, plasma estriol assays proved to be precise, specific and accurate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32741/1/0000110.pd

Endogenous sex steroid hormones and glucose in a South‐Asian population without diabetes: the Metabolic Syndrome and Atherosclerosis in South‐Asians Living in America pilot study

AimsTo examine the associations between endogenous sex steroid hormones (oestradiol, testosterone and sex hormone‐binding globulin) with diabetes risk in a South‐Asian population living in the USA.MethodsWe used data from the Metabolic Syndrome and Atherosclerosis in South‐Asians Living in America pilot study. The analytical sample included 60 women and 45 men of Asian Indian origin living in the San Francisco Bay Area, who were free from diabetes and cardiovascular disease and did not use exogenous sex steroids. Sex steroid hormone levels were assessed by validated conventional radioimmunoassays, and visceral and hepatic adiposity were assessed by computed tomography. We used multivariable regression to examine the association between endogenous sex steroid hormone levels (log‐transformed) and fasting glucose and 2‐h glucose levels in a series of sex‐stratified models adjusted for age, waist circumference, visceral and hepatic adiposity, and insulin resistance.ResultsIn age‐adjusted models, lower levels of sex hormone‐binding globulin (β = −0.18, 95% CI −0.30, −0.06) and higher levels of free testosterone (β = 0.14, 95% CI 0.02, 0.26) were associated with elevated fasting glucose levels in South‐Asian women, whereas lower levels of sex hormone‐binding globulin (β = −0.14, 95% CI −0.26, −0.02) and lower levels of total testosterone (β = −0.12, 95% CI −0.24, 0.00) were associated with elevated fasting glucose levels in South‐Asian men. Adjustment for waist circumference, visceral adiposity and insulin resistance attenuated most of these associations, while adjustment for hepatic adiposity strengthened some of the observed associations. Similar results were found for 2‐h glucose levels.ConclusionsResults were consistent with previous research, which suggests that endogenous sex steroid hormones are a risk factor for diabetes across multiple race/ethnic groups. Additional studies are needed to determine whether visceral fat is a mediator or confounder of associations between sex steroid hormone and glucose levels.What's new?This is the first study to examine the associations between sex steroid hormones and glucose levels in a population‐based sample of South‐Asian people without diabetes living in the USA.This work adds to a small body of literature examining sex steroid hormones in South‐Asian people, a population at high risk for dysglycaemia.Although sex hormone‐binding globulin has been hypothesized to be a marker of hepatic adiposity, associations of sex hormone‐binding globulin with glucose were not attenuated by hepatic adiposity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113125/1/dme12642.pd

Breast epithelial cell proliferation is markedly increased with short-term high levels of endogenous estrogen secondary to controlled ovarian hyperstimulation

Oocyte donors have high serum estradiol (E2) levels similar to the serum levels seen in the first trimester of pregnancy. We report in this article our studies comparing cell proliferation, Ki67 (MIB1), and estrogen and progesterone receptor levels (ERα, PRA, and PRB) in the breast terminal duct lobular units of oocyte donors, women in early pregnancy, and in normally cycling women. Breast tissue and blood samples were obtained from 10 oocyte donors, and 30 pregnant women at 5–18 weeks of gestation. Breast tissue samples were also obtained from 26 normally cycling women. In the oocyte donors: peak E2 (mean ~15,300 pmol/l) was reached on the day before oocyte (and tissue) donation; peak progesterone (P4; mean 36.3 nmol/l) was reached on the day of donation; Ki67 was positively associated with level of E2, and the mean Ki67 was 7.0% significantly greater than the mean 1.8% of cycling women. In the pregnant women: mean E2 rose from ~2,000 pmol/l at 5 weeks of gestation to ~27,000 pmol/l at 18 weeks; mean P4 did not change from ~40 nmol/l until around gestational week 11 when it increased to ~80 nmol/l; mean Ki67 was 15.4% and did not vary with gestational age or E2. Oocyte donors have greatly increased levels of E2 and of breast-cell proliferation, both comparable in the majority of donors to the levels seen in the first trimester of pregnancy. Whether their short durations of greatly increased E2 levels are associated with any long-term beneficial effects on the breast, as occurring in rodent models, is not known

The temporal reliability of serum estrogens, progesterone, gonadotropins, SHBG and urinary estrogen and progesterone metabolites in premenopausal women

BACKGROUND: There is little existing research to guide researchers in estimating the minimum number of measurement occasions required to obtain reliable estimates of serum estrogens, progesterone, gonadotropins, sex hormone-binding globulin (SHBG), and urinary estrogen and progesterone metabolites in premenopausal women. METHODS: Using data from a longitudinal study of 34 women with a mean age of 42.3 years (SD = 2.6), we calculated the minimum number of measurement occasions required to obtain reliable estimates of 12 analytes (8 in blood, 4 in urine). Five samples were obtained over 1 year: at baseline, and after 1, 3, 6, and 12 months. We also calculated the percent of true variance accounted for by a single measurement and intraclass correlation coefficients (ICC) between measurement occasions. RESULTS: Only 2 of the 12 analytes we examined, SHBG and estrone sulfate (E(1)S), could be adequately estimated by a single measurement using a minimum reliability standard of having the potential to account for 64% of true variance. Other analytes required from 2 to 12 occasions to account for 81% of the true variance, and 2 to 5 occasions to account for 64% of true variance. ICCs ranged from 0.33 for estradiol (E(2)) to 0.88 for SHBG. Percent of true variance accounted for by single measurements ranged from 29% for luteinizing hormone (LH) to 92% for SHBG. CONCLUSIONS: Experimental designs that take the natural variability of these analytes into account by obtaining measurements on a sufficient number of occasions will be rewarded with increased power and accuracy