Estimation 3-Estradiol

In order to obtain quicker methods without chromatography, the more specific antibodies A-2 and A-3 have been used to estimate estradiol-17/8 and estriol, respectively. These two antibodies were incubated directly with the residues after extraction of serum with dichloromethane. 

Johnson AC, Williams RJ (2004) A model to estimate influent and effluent concentrations of estradiol, estrone, and ethinylestradiol at sewage treatment works. Environ Sci Technol 38 3649-3658... 

Fig. 7.3.2. Effect of estradiol and BP-5 on MCF7 cell proliferation and gene expression. MCF7 cells were grown in estrogen-depleted medium. Estradiol or BP-5 were added to cultures and cell number (proliferation), protein determination (PgR and pS2), gene expression (pS2 mRNA) and luciferase expression were estimated at the appropriate times, as indicated in the Methods Section.

Estimate the Ki0Vi values at 25°C of the following compounds based on the experimental Ki0Vi values of the indicated structurally related compounds (a) benzoic acid dimethylaminoethyl ester from benzoic acid ethyl ester (log Kiaw = 2.64), (b) the insecticide methoxychlor from DDT (log Ki0Vi = 6.20), (c) the insecticide fenthion from parathion [log Kiow = 3.83, see 111. Ex. 7.2, Answer (d)], and (d) the hormone estradiol from testosterone [log Ki0Vi = 3.32, see 111. Ex. 7.2, Answer (e)]. 

Santen RJ, Lee JS, Wang S, Demers LM, Mauras N, Wang H et al (2008) Potential role of ultra-sensitive estradiol assays in estimating the risk of breast cancer and fractures. Steroids 73 1318-1321... 

The parameter K may be estimated from the 3 estradiol solubility data presented in Figure 2, assuming Henry s law is obeyed,... 

Hydroxapatite has proved to be very useful for the separation of free and antibody-bound steroid in the immunoassay of various steroids. Successful immunoassays have been set up, using hydroxyapatite, for the estimation of plasma testosterone, estradiol-17/3, 17a-hydroxyproges-terone, and progesterone. No steroid so far examined has been found to be bound to hydroxyapatite. Some other low molecular weight compounds, for which immunoassays are available, have also been found not to be bound to hydroxyapatite (see the table), and it may therefore be possible to use hydroxyapatite in immunoassays for compounds other than steroids. 

Estrone, estradiol-17/3, and estriol have been estimated in serum by means of RIA including a step of separation with Sephadex G-25 fine minicolumns. 

After diethyl ether extraction from 1-ml serum samples and chromatography on Sephadex LH-20 columns, estrone and estradiol-17/3 were estimated after incubation by the method of Hotchkiss et al. with antibody A-1. 

The relative estrogenic potency of a compound has been estimated by many different biological assays. Some values found in the literature are shown in Tables 5.3.1 and Table 5.3.2. The values are all given as Estradiol equivalency factors (EEF), defined as EC50 of the compound relative to the EC50 of 17ft-estradiol. 

Two synthetic estrogens commonly used in OCs in the United States, ethinyl estradiol (EE) and mestranol, differ only by the presence of a methyl group attached to mestranol at the C-3 site. Mestranol, which must be converted by the liver to ethinyl estradiol before it is pharmacologically active, is estimated to be 50% less potent than EE. ... 

Sun, L, Zhou, Y, Genrong, L. and Li, S.Z. (2004) Molecular electronegativity-distance vector (MEDV-4) a two-dimensional QSAR method for the estimation and prediction of biological activities of estradiol derivatives. J. Mol. Struct. (Theochem), 679, 107—113. 

The best method for urinary estrogens of clinical importance is that devised by Brown (B20, B21). This depends on the modification of the Kober-Ittrich color reaction to provide an extremely sensitive fluorescence reaction (see also S2). Acid hydrolysis (15 minutes) is followed by either extraction (2X1 volume) evaporation to dryness a partition between petroleum ether-benzene and water (estriol) and 1.6% NaOH (estradiol, estrone). The two solutions are methylated (10 minutes) and extracted with ether the ether is evaporated, and the residues are run on alumina columns. In the original procedure the less specific and sensitive form of the Kober reaction required more extensive purification one technician could complete four estimations in 1.5-2 days. The new procedure enables four determinations to be made every 5-6 hours. An ultrarapid version of this method for specialized obstetric use has been devised by Gemzell and his group and will be published shortly. By this method, twelve samples can be measured in 3 hours by one technician. 

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