Radioimmunoassay of plasma estrogens

Wu, Chung Hsuen; Lundy, Laurence E.

doi:10.1016/s0039-128x(71)80174-5

Cited by 275 publications

(67 citation statements)

References 7 publications

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“…CBG was measured directly by radioimmunoassay (RIA); the intra-and interassay coefficients of variation (CVs) were 7.8 and 11%, respectively. Estradiol was measured by RIA after extraction with LH20 column chromatography in a modification of the procedure by Wu and Lundy (1971). The intra-assay CV was 3.2%, and the interassay CV was 9.2%.…”

Section: Methodsmentioning

confidence: 99%

Testosterone Suppression of CRH-Stimulated Cortisol in Men

Rubinow

Roca

Schmidt

et al. 2005

Neuropsychopharmacol

134

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Despite observations of age-dependent sexual dimorphisms in hypothalamic-pituitary-adrenal (HPA) axis activity, the role of androgens in the regulation of HPA axis activity in men has not been examined. We assessed this role by performing CRH stimulation tests in 10 men (ages 18-45 years) during gonadal suppression with leuprolide acetate and during testosterone addition to leuprolide. CRHstimulated cortisol levels as well as peak cortisol and greatest cortisol excursion were significantly lower (po0.05, 0.005, and 0.01, respectively) during testosterone replacement compared with the induced hypogonadal condition (leuprolide plus placebo); cortisol area under the curve was lower at a trend level (po0.1). Paradoxically, CRH-stimulated corticotropin (ACTH) was increased significantly during testosterone replacement (po0.05). The cortisol : ACTH ratio, a measure of adrenal sensitivity, was lower during testosterone replacement (po0.1). A mixed effects regression model showed that testosterone but not estradiol or CBG significantly contributed to the variance of cortisol. These data demonstrate that testosterone regulates CRH-stimulated HPA axis activity in men, with the divergent effects on ACTH and cortisol suggesting a peripheral (adrenal) locus for the suppressive effects on cortisol. Our results further demonstrate that the enhanced stimulated HPA axis activity previously described in young men compared with young women cannot be ascribed to an activational upregulation of the axis by testosterone.

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Section: Methodsmentioning

confidence: 99%

Testosterone Suppression of CRH-Stimulated Cortisol in Men

Rubinow

Roca

Schmidt

et al. 2005

Neuropsychopharmacol

134

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“…El and E2 were measured by radioimmunoassay using a modification of the method of Wu & Lundy (1971). The intra-assay coefficients of variation (CV) based on control pools assayed concurrently were 6.8% for El, and 11.4% for E2.…”

Section: Methodsmentioning

confidence: 99%

Serum oestrogen levels in postmenopausal women: comparison of American whites and Japanese in Japan

Shimizu

Ross²,

Bernstein³

et al. 1990

Br J Cancer

156

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Summary Serum oestrone (El), oestradiol (E2) and sex hormone binding globulin (SHBG) levels were studied in postmenopausal Japanese women in Japan (n = 91) and postmenopausal American white women (n = 38). The Japanese women were deliberately chosen to be from a rural agricultural area in order to get samples which represent as closely as possible the traditional Japanese 'lifestyle' that gave rise to the low rates of breast cancer in Japan. El levels were 47%, and E2 levels 36%, greater in the American women; these differences were only reduced to 43% and 27% after adjustment for the lower weight of the Japanese. These results were all statistically highly significant. There was little difference in SHBG levels between the Japanese and the American women. These results for El and E2 could be an important part of the explanation why Japanese and American breast cancer rates continue to diverge further after the menopause.There is considerable evidence that oestrogens are involved in the aetiology of breast cancer and that increased blood levels of oestrogen in postmenopausal breast cancer patients are one marker of high risk (Key & Pike, 1988;Bernstein et al., 1990). The incidence rates for breast cancer in Japan are substantially lower than those in the USA and European countries (Muir et al., 1987), and some systematic pathological and clinical differences between breast cancer diagnosed in Japan and western countries have been reported (Wynder et al., 1963;Chabon et al., 1974). These observations suggest that there may be important differences in endocrine function among residents in these areas, but there are surprisingly few data on blood hormone levels in healthy populations from these countries. We report here a study comparing serum oestrogen and sex-hormone-binding globulin (SHBG) levels of post-menopausal Japanese women in Japan to those of white women in the USA. Subjects and methodsThe Japanese subjects were volunteers residing in rural areas of Miyagi, a prefecture in north-east Japan. These women were mainly from rice farming families. We first contacted them at a general medical screening clinic for the healthy elderly sponsored by their farmer's union, informing them of the purpose of our study and asking for their cooperation. The subjects in the USA were American non-Latino volunteers from a retirement community in Southern California, who had a blood sample drawn during a well-patient visit to a local health clinic. All women had to have intact ovaries, be postmenopausal, and be 60 to 70 years of age. Ninety-one women were sampled in Japan; 38 women were sampled in California. Women with any past or present endocrine disease, or who had used steroid hormones during the previous 12 months, or had more than 12 months total use of steroid hormones, were excluded.All subjects were asked to provide information on a series of factors related to breast cancer risk and, possibly, to hormonal status, including ages at menarche, menopause, and first full-term pregnancy, number of children, and present h...

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“…Blood was collected into ice-cold, heparinized syringes, centrifuged immediately and the plasma was stored at -15\s=deg\C until analysis. The plasma was extracted with 10 vols redistilled diethyl ether and chromatographed on micro-columns of Sephadex (Wu & Lundy, 1971). The oestrone and oestradiol fractions thus separated were subjected to radioimmunoassay by the method of Peterson & Common (1972), using antisera against oestradiol-17ß-17-BSA and oestradiol-17/J-6-rBSA, respectively.…”

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confidence: 99%

Oestrogens in Bovine Fetal and Maternal Plasma Near Term

Peterson¹,

Hunter²,

Welch³

et al. 1975

Reproduction

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turition, little is known of the source of this oestrogen rise in the cow. It seemed pertinent, therefore, to determine the levels of oestrogens in fetal and maternal plasma over the last 3 weeks of gestation. In the present paper, the levels of free oestrone and oestradiol-17\g=b\ in the maternal jugular and utero-ovarian vein plasma and in fetal vena cava plasma in relation to the initiation of parturition in the cow were determined by radioimmunoassay.Catheters were implanted surgically into the maternal utero-ovarian and jugular veins and into the fetal posterior vena cava through the fetal saphenous vein in three cows during the last third of gestation. Fetal and maternal blood samples were taken twice daily until parturition; when calving was imminent, maternal utero-ovarian samples were taken more frequently. Blood was collected into ice-cold, heparinized syringes, centrifuged immediately and the plasma was stored at -15\s=deg\C until analysis. The plasma was extracted with 10 vols redistilled diethyl ether and chromatographed on micro-columns of Sephadex (Wu & Lundy, 1971). The oestrone and oestradiol fractions thus separated were subjected to radioimmunoassay by the method of Peterson & Common (1972), using antisera against oestradiol-17ß-17-BSA and oestradiol-17/J-6-rBSA, respectively. Oestrone cross-reacted 56% with the oestradiol-17ß-17-BSA antiserum and oestradiol-17a cross-reacted 1-9% with the antiserum against oestradiol-17/Í-6-BSA. Over the range of 0-01 to 1-0 ng, recoveries of oestrone and oestradiol-17 ß were of the order of 70 to 80% and the within-assay coefficient of variation was 10 to 12%. The between-assay coefficient of varia¬ tion, calculated from control samples run in duplicate with each assay was 15%. The sensitivity of the method, determined from the variability of the reagent blanks, was 5 pg/ml for oestrone and 4 pg/ml for oestradiol-17ß. The results in this paper have been corrected for procedural losses.The mean values for three cows are presented in Text-fig.

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Radioimmunoassay of plasma estrogens

Cited by 275 publications

References 7 publications

Testosterone Suppression of CRH-Stimulated Cortisol in Men

Testosterone Suppression of CRH-Stimulated Cortisol in Men

Serum oestrogen levels in postmenopausal women: comparison of American whites and Japanese in Japan

Oestrogens in Bovine Fetal and Maternal Plasma Near Term

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