Radioimmunoassay of Estradiol-17β Without Chromatography

England, Barry G.; Niswender, Gordon D.; Midgley, A. Rees

doi:10.1210/jcem-38-1-42

Cited by 210 publications

(50 citation statements)

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“…The sensitivity, intra-, and interassay coefficient of variation of the estradiol assays were 3.9 pg, 7, and 12% respectively. Cross-reactivity of androstenedione in estradiol assay is !0.001% (England et al 1974). The sensitivity, intra-, and interassay coefficient of variation of the androgen assay were 1.5 pg, 5, and 9% respectively.…”

Section: Steroid Response To Vip Stimulationmentioning

confidence: 84%

Participation of vasoactive intestinal polypeptide in ovarian steroids production during the rat estrous cycle and in the development of estradiol valerate-induced polycystic ovary

Parra

Fiedler²,

Luna³

et al. 2007

Reproduction

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Vasoactive intestinal polypeptide (VIP) stimulates estradiol and progesterone release from ovarian granulosa cells in vitro. Very little information is available as to the role VIP plays in the control of steroid secretion during reproductive cyclicity and in ovarian pathologies involving altered steroid secretion. In this study, we determined the involvement of VIP in regulating ovarian androgen and estradiol release during estrous cyclicity and estradiol valerate (EV)-induced polycystic ovarian development in rats. Our findings show that androgen and estradiol release from ovaries obtained during different stages of rat estrous cycle mimic cyclic changes in steroid release observed in vivo with maximal release occurring during late proestrus. VIP increased androgen release from ovaries of all cycle stages except late proestrus and estradiol release from all cycle stages. Increases in VIP-induced androgen and estradiol release were maximal at early proestrus. Inclusion of saturating concentrations of androstenedione increased magnitude of VIP-induced estradiol release at diestrus and estrus but not proestrus. Magnitude of VIP-induced androgen and estradiol release tended to be greater in the ovaries from EV-treated rats with polycystic ovary compared with estrous controls. At the tissue level, ovarian VIP concentration was cycle stage dependent with highest level seen in diestrus. Maximum concentration of VIP was found in EV-treated rats. Changes in VIP were inversely related to changes in ovarian nerve growth factor, a neuropeptide involved in ovarian androgen secretion. These results strongly suggest that intraovarian VIP participates in the control of estradiol secretion during the rat estrous cycle and possibly in the maintenance of increased ovarian estradiol secretory activity of EV-treated rats.

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Section: Steroid Response To Vip Stimulationmentioning

confidence: 84%

Participation of vasoactive intestinal polypeptide in ovarian steroids production during the rat estrous cycle and in the development of estradiol valerate-induced polycystic ovary

Parra

Fiedler²,

Luna³

et al. 2007

Reproduction

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“…By the early 1970s, radioimmunoassays for estradiol, estrone, and estrone sulfate had been developed which had sensitivities as low as 5 pg/ml (34)(35)(36)(37)(38)(39)(40). Antibodies against estradiol were discovered subsequently that permitted sensitivities as low as 2 pg/ml (41,42). The ultrasensitive RCBA, by exploiting the potential for signal amplification in a genetically engineered biological system, further increases the sensitivity of estrogen measurement by two orders of magnitude.…”

Section: Discussionmentioning

confidence: 99%

Estrogen levels in childhood determined by an ultrasensitive recombinant cell bioassay.

Klein¹,

Baron²,

Colli³

et al. 1994

J. Clin. Invest.

351

223

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We hypothesized that estradiol levels are higher in prepubertal girls than in prepubertal boys and that this greater secretion of estradiol might drive the more rapid epiphyseal development and earlier puberty in girls. Since previous estradiol assays have lacked adequate sensitivity to test the hypothesis of higher estradiol levels in girls, we developed a new ultrasensitive assay to measure estrogen levels. The assay uses a strain of Saccharomyces cerevisiae genetically engineered for extreme sensitivity to estrogen. Yeast were transformed with plasmids encoding the human estrogen receptor and an estrogen-responsive promoter fused to the structural gene for f-galactosidase. Ether extracts of 0.8 ml of serum were incubated with yeast for 8 h and the 38-galactosidase response was used to determine estrogen bioactivity relative to estradiol standards prepared in charcoalstripped plasma. The assay was highly specific for estradiol with < 3 % cross-reactivity with estrone, estriol, or estradiol metabolites. The detection limit was < 0.02 pg/ml estradiol equivalents (100-fold lower than existing assays). Using this assay, we measured estrogen levels in 23 prepubertal boys (9.4±2.0 yr) and 21 prepubertal girls (7.7+1.9 [SD] yr). The estrogen level in girls, 0.6+0.6 pg/ml estradiol equivalents, was significantly greater than the level in boys, 0.08+0.2 pg/ml estradiol equivalents (P < 0.05). We conclude that the ultrasensitive recombinant cell bioassay for estrogen is approximately 100-fold more sensitive than previous estradiol assays, that estrogen levels are much lower prepubertally, in both sexes, than reported previously, and that prepubertal girls have 8-fold higher estrogen levels than prepubertal boys. (J. Clin. Invest. 1994Invest. . 94:2475Invest. -2480

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“…To determine whether the steroid concentrations in the culture media were the result of de-novo synthesis or passive diffusion from the follicular fluid, 6 ewes were ovariectomized and follicles dissected from the surrounding ovarian stroma as described previously (Webb & England, 1982 (England, Niswender & Midgley, 1974). All samples were subjected to extraction and Sephadex chromatography to remove all other major cross-reacting substances (Hauger et al, 1977).…”

Section: Validation Of the Incubation Proceduresmentioning

confidence: 99%

Relationship between LH receptor concentrations in thecal and granulosa cells and in-vivo and in-vitro steroid secretion by ovine follicles during the preovulatory period

Webb¹,

England²

1982

Reproduction

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Summary. Ewes were ovariectomized before (Group 1, N = 5) or after (Group 2, N = 6) the peak of the preovulatory gonadotrophin surge. Ovarian secretion rates of oestradiol and testosterone were significantly higher in Group 1 than in Group 2. The presence of high levels of LH receptors in both thecal and granulosa cells was used to identify ovulatory from non-ovulatory follicles. There was a significant fall in the LH receptor concentration in the thecal and granulosa cells of ovulatory follicles after the peak of the preovulatory gonadotrophin surge. Ovulatory follicles in Group 1 produced significantly more oestradiol and testosterone in vitro than did those in Group 2. In both groups ovulatory follicles secreted significantly more oestradiol in vitro than did non-ovulatory follicles. Follicular fluid oestradiol concentrations were similar in pattern to the in-vitro oestradiol secretion activity in ovulatory and non-ovulatory follicles. However, follicular fluid testosterone concentrations were significantly higher in non-ovulatory follicles than in ovulatory follicles. Incubation of follicles with 250 ng testosterone/ml did not significantly alter the in-vitro oestradiol secretion rate in any of the groups of follicles except for Group 2 non-ovulatory follicles in which oestradiol accumulation increased. The number of thecal and granulosa cell LH receptors was significantly correlated with follicular fluid oestradiol concentrations in ovulatory follicles and with in-vitro oestradiol production by Group 1 ovulatory follicles. It is suggested that the fall in oestradiol secretion rates, which occurs after the peak of the preovulatory gonadotrophin surge, may be due to a decrease of aromatase activity associated with a fall in the concentration of LH receptors and is not due to a lack of the oestrogen precursor testosterone. The elevated concentration of testosterone and low oestradiol concentrations in non-ovulatory follicles compared with ovulatory follicles are probably due to an inactive aromatase system, perhaps associated with the lack of granulosa cell LH receptors.

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Radioimmunoassay of Estradiol-17β Without Chromatography

Cited by 210 publications

References 0 publications

Participation of vasoactive intestinal polypeptide in ovarian steroids production during the rat estrous cycle and in the development of estradiol valerate-induced polycystic ovary

Participation of vasoactive intestinal polypeptide in ovarian steroids production during the rat estrous cycle and in the development of estradiol valerate-induced polycystic ovary

Estrogen levels in childhood determined by an ultrasensitive recombinant cell bioassay.

Relationship between LH receptor concentrations in thecal and granulosa cells and in-vivo and in-vitro steroid secretion by ovine follicles during the preovulatory period

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