Estradiol occurrence

Effective removal of the estrogens 17 3-estradiol, estrone, and 17a-ethynylestradiol has been achieved using ozone under conditions that simulated those used for water treatment (Deborde et al. 2005). Analysis of the products showed the occurrence of two reactions ... 

Gonadotropins are used to treat infertility in women with potentially functional ovaries who have not responded to other treatments. The therapy is designed to simulate the normal menstrual cycle as far as is practical. A common protocol is daily injections of menotropins for 9 to 12 days, until estradiol levels are equal to that in a normal woman, followed by a single dose of hCG to induce ovulation. Two problems with this treatment are risks of ovarian hyperstimulation and of multiple births. Ovarian hyperstimulation is characterized by sudden ovarian enlargement associated with an increase in vascular permeability and rapid accumulation of fluid in peritoneal, pleural, and pericardial cavities. To prevent such occurrences, ovarian development is monitored during treatment by ultrasound techniques and by measurements of serum levels of estradiol. 

Pharmacodynamics Serum progesterone and 17-P-estradiol levels are considered reliable indicators for the occurrence of ovulation. Since progesterone and 17-f)-cstradiol levels were comparable for both treatments, and progesterone serum concentrations did not exceed 1.4 ng/mL (as defined in this study, progesterone concentrations above 1.4 ng/mL on day 20 of a menstrual cycle indicated ovulation) for both treatments, it was concluded that Drug XYZ administration did not affect the contraceptive effect of ethinylestradiol-based oral contraceptives and that no ovulation occurred in any of the subjects. 

Specificity of an immunoassay is usually measured by determining the extent that compounds that are structurally similar to the test analyte react in the assay. The determination of the assay reactivity of an array of potential cross-reactant is routinely performed in immunoassay development. A panel of suspect cross-reactant, should be selected on the basis of structural similarities to the test analyte and on the expected occurrence along with the test analyte in the sample. Thus, an immunoassay specific for 17/1-estradiol should be tested for reactivity with estrone, estriol, 17a-estraiol and testosterone. Other compound testing might also be indicated. 

Emmersen, B.K. and I.M. Petersen. Natural occurrence and experimental induction by estradiol-17/3, of a lipophosphoprotein (vitellogenin) in flounder (Platichthys flesus, L.). Comp. Biochem. Physiol. 54B 443-446, 1976. 

The HPG axis is responsible for the cyclic hormone secretion that regulates and controls ovulation and plays a major role in menstruation-related disorders. The menstrual cycle is characterized by cyclic alterations in the production of gonadal hormones (estradiol and progesterone), pituitary hormones (gonadatropins, prolactin, growth hormone), melatonin, and cortisol and in temperature rhythms. Menstruation-related disorders are likely the result of a complex interaction between ovarian steroids and central neurotransmitters, neurohormones, and neuropeptides. The occurrence of physical... 

The sublimation temperature and the distance of the collecting surface from the material undergoing sublimation have a great influence on the form and size of the crystals produced. The occurrence of polymorphic modifications depends on the temperature of sublimation. In general, it may be assumed that unstable crystals form preferentially at lower temperatures, while at higher temperatures stable forms are to be expected. Nevertheless, mixtures consisting of several modifications are frequently found together. This is the case for barbital and for estradiol benzoate. It should be obvious that the sublimation technique is applicable only to those compounds that are thermally stable. 

In order to do this, we must use a random number generator with the same probability of an occurrence as we expect would happen with the estradiol. In addition, the random number generator should have the same variability (called variance) as the biological process. And, we need to have four random number generators acting simultaneously. 

It seems to have been assumed that the occurrence of steroidal estrogens is confined to mammals. However, reports have been published which indicate the presence of estrone, estradiol-17/3, and estriol in birds (Hurst et al., 1957 Layne et al., 1958) and fish (Wotiz et al., 1958a Dean and Chester Jones, 1959). But the only estrogens obtained in crystalline form were estradiol-l7/3 from the droppings of laying hens (MacRae et al., 1959a) and estrone as well as estradiol-17/3 from the ovaries of the dogfish (Wotiz et al., 1960). 

A long term study on probability of tumor formation in rats given ethy-nyl estradiol, BDH 2700 (10) and megestrol acetate has been published . The chloroethynyl compound (10) increased the incidence of mammary adenocarcinoma, A reduced occurrence of tumors was observed with other combinations. 

The study of the metabolism of estrogens has centered principally on the interconversion of these four biologically active 18-carbon steroids estrone (XC), estradiol-17 S (XCI), estradiol-17a (XCII), and estriol-16a, 17/3 (XCIII). Since the recovery of the estrogens after administration of an 18-carbon steroid has been low, much of the identification has been based on various colorimetric determinations or bioassay. The phenolic fraction upon which these analyses have been performed has been subfractionated by partition between two immiscible liquids and by countercurrent distribution. However, there have been sufficient experiments with massive doses of estrogens in which the compounds have been isolated and characterized to give reliability to the occurrence of the interconversions, as indicated in Fig. 19. Estradiol-17/8 (XCI) is the most potent estrogen and the less active estrone (XC) and estriol (XCIII) are considered to be its metabolic transformation products. Thus, after administration of estradiol-17/3, estrone and estriol were found in the urine of man and rabbit estriol has also been obtained after... 

Warrier, S.R., Tirumalai, R., and Subramoniam, T. (2001) Occurrence of vertebrate steroids, estradiol 17 3 and progesterone in the reproducing females of the mud crab Scylla serrata. Comp. Biochem. Physiol, 130A, 283-294. 

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