Estradiol molecule

Fig. 2.1. Chemical structure of several SERMs in triphenylethylene group. The estradiol molecule is also included as a comparative reference...

Nevertheless, it may be possible to construct a displacement type system for the detection of j8-estradiol by labelling the molecule at C-17 and using DEAEMA as the functional monomer. Alternatively, the reporter itself could be used as the template molecule. The smaller jS-estradiol molecule should enjoy easy access to the binding sites and be able to compete effectively with the reporter. Finally, this technique may find more success for the analysis of corticosteroids [45], which possess... 

The steroids as a group tend to be poorly soluble in water. Their complex stmcture makes prediction of solubility somewhat difficult, but one can generally rationalise, post hoc, the solubility values of related steroids. Table 5.6 gives solubility data for 14 steroids. As examples, the substitution of an ethinyl group has conferred increased solubility on the estradiol molecule, as would be expected. Estradiol benzoate with its 3-OH substituent is much less soluble than the parent estradiol because of the loss of the hydroxyl and its substitution with a hydrophobic group. The same relationships are seen in testosterone and testosterone propionate. As both estradiol benzoate and testosterone propionate are oil soluble, they are used as solutions in castor oil and sesame oil for intramuscular and subcutaneous injection (see Chapter 9). 

Bisphenol-A and 17a-thinylestradiol both have estrogenic activity and both have structures resembling the active portion of the estradiol molecule (Figure 5.29). /3-Sitosterol does have a ring structure with an -OH group, but... 

Equally important is the high affinity binding of the Tc-estradiol analog to the estradiol receptor. The functional group chosen must not interfere with this binding and must be attached to the estradiol molecule at a point which does not interfere with binding to the receptor. The ability of the Tc-compound to... 

Although estrone and estradiol (26) have both been isolated from human urine, it has recently been shown that it is the latter that is the active compound that binds to the so-called estrogen receptor protein. Reduction of estrone with any of a large number of reducing agents (for example, any of the complex metal hydrides) leads cleanly to estradiol. This high degree of stereoselectivity to afford the product of attack at the alpha side of the molecule is characteristic of many reactions of steroids. 

C03-0080. A particular oral contraceptive contains 0.035 mg ethynyl estradiol in each pill. The formula of this compound is C20 H24 O2. How many moles of ethynyl estradiol are there in one pill How many molecules is this How many carbon atoms are in a 0.035-mg sample of ethynyl estradiol What mass of carbon is this ... 

Competitive immunoassays may also be used to determine small chemical substances [10, 11]. An electrochemical immunosensor based on a competitive immunoassay for the small molecule estradiol has recently been reported [11]. A schematic diagram of this immunoassay is depicted in Fig. 5.3. In this system, anti-mouse IgG was physisorbed onto the surface of an SPCE. This was used to bind monoclonal mouse anti-estradiol antibody. The antibody coated SPCE was then exposed to a standard solution of estradiol (E2), followed by a solution of AP-labeled estradiol (AP-E2). The E2 and AP-E2 competed for a limited number of antigen binding sites of the immobilized anti-estradiol antibody. Quantitative analysis was based on differential pulse voltammetry of 1-naphthol, which is produced from the enzymatic hydrolysis of the enzyme substrate 1-naphthyl phosphate by AP-E2. The analytical range of this sensor was between 25 and 500pg ml. 1 of E2. 

Some steroid molecules (estrone, estradiol, and estriol) have phenolic hydroxyl in the ring A (Figure 29.12) and therefore, are able to react as free radical scavengers. In 1987, Japanese authors [264,265] showed that all these compounds inhibited iron adriamycin- or iron ADP-ascorbate-dependent phospholipid and liposomal lipid peroxidation. Later on, most attention was drawn to the study of antioxidative properties of estradiol-17(3 (estrogen E2) it has been proposed that E2 antioxidant activity may contribute to cardioprotection observed after estrogen therapy in postmenopausal women. The necessity for the phenolic hydroxyl has been shown by studying the effects of several estrogens on LDL oxidation. It was found [266]... 

The spatial conformation that the ligand-receptor acquires, particularly the spatial disposition that helix 12 of the LBD attains when it binds to estradiol, is key for the subsequent recruitment of the transcription cofactors (Fig. 1.9). Indeed, the arrival of estradiol restructures the entire domain, making helix 12 rotate and close the hole where the leucine zipper sequence of the corepressor had been lodged before (Fig. 1.10). Consequently, both molecules, corepressor and receptor, lose their affinity and their bond is undone. Another structure capable of interacting with gene transcription coactivators is formed at the same place on the receptor (MacGregor et al. 1998 McDonnell et al. 2002). 

Monodisperse microspheres imprinted with theophylline or 17 (3-estradiol were used in competitive radioimmunoassays showing the MIP s high selectivity for the template molecule. In this case the assay is based on the competition of the target molecule with its radioactively labeled analogue for a limited number of antibody binding sites [77,118]. Figure 15 demonstrates that displacing the radioactively marked theophylline from the imprinted polymer was only possible with theophylline as competitor. Structurally related molecules showed effects solely at elevated concentrations [77]. 

Gaulin-Glaser T, Watson CA, Pardi R, and Bender JR [1996] Effects of 17/3-estradiol on cytokine-induced endothelial cell adhesion molecule expression. J Clin Invest 98 36-42... 

Astatosteroids. Several complex steroid molecules have been astatinated via their chloromercuriderivatives a mixture of 2-as-tatoestradiol (I), 4-astatoestradiol (II), and 2-astato-4-iodoestradiol (III) was obtained with yields of 55, 19, and 18%, respectively (170). Estradiol was mercurated by Hg(CH3COO)2 in a C2H50H-water solution for 16 hours at room temperature, and then allowed to react with At in H2SO4 in the presence of KI3 for 1 hour. The products were separated and identified by TLC (170). 

Examples are shown in Fig. 23.9. Stereochemistry is indicated by dotted lines (a-bonds, behind the plane) and solid lines (P-bonds, in front of the plane) of any substituents on the rings. The sex hormones are the molecules mainly responsible for differentiating the sexes. The difference between testosterone and progesterone is a hydroxy versus an acetyl group. The natural sex hormones are used to treat prostate cancer, to alleviate menopausal distress, and to correct menstrual disorders. Other common natural steroids are estradiol, cholesterol, and cortisone. Infamous... 

Esters of A - hydro x y s u c c i n i in i d c are also used to carry out chemical modification of peptides, proteins, and other biological molecules by acylation of nucleophilic groups in these molecules. For example, detection of estradiol antibodies can be accomplished using... 

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