Estrone glucuronide, or estrone-3-D-glucuronide, is a conjugated metabolite of

estrone Estrone (E1), also spelled oestrone, is a steroid, a weak estrogen, and a minor female sex hormone. It is one of three major endogenous estrogens, the others being estradiol and estriol. Estrone, as well as the other estrogens, are synthesized ...

. It is formed from estrone in the

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it ...

by UDP-glucuronyltransferase via attachment of glucuronic acid and is eventually excreted in the

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellular ...

by the

kidney The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blo ...

s. It has much higher

water solubility An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be rep ...

than does estrone. Glucuronides are the most abundant estrogen conjugates and estrone glucuronide is the dominant metabolite of estradiol. When

exogenous In a variety of contexts, exogeny or exogeneity () is the fact of an action or object originating externally. It contrasts with endogeneity or endogeny, the fact of being influenced within a system. Economics In an economic model, an exogeno ...

estradiol is administered orally, it is subject to extensive

first-pass metabolism The first pass effect (also known as first-pass metabolism or presystemic metabolism) is a phenomenon of drug metabolism whereby the concentration of a drug, specifically when administered orally, is greatly reduced before it reaches the system ...

(95%) in the intestines and

. A single administered dose of estradiol is absorbed 15% as

, 25% as

estrone sulfate Estrone sulfate, also known as E1S, E1SO4 and estrone 3-sulfate, is a natural, endogenous steroid and an estrogen ester and conjugate. In addition to its role as a natural hormone, estrone sulfate is used as a medication, for instance in menop ...

, 25% as

estradiol glucuronide Estradiol glucuronide, or estradiol 17β-D-glucuronide, is a conjugated metabolite of estradiol. It is formed from estradiol in the liver by UDP-glucuronyltransferase via attachment of glucuronic acid and is eventually excreted in the urine ...

, and 25% as estrone glucuronide. Formation of

estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal ac ...

glucuronide conjugates is particularly important with oral estradiol as the percentage of estrogen glucuronide conjugates in circulation is much higher with oral ingestion than with parenteral estradiol. Estrone glucuronide can be reconverted back into estradiol, and a large circulating pool of estrogen glucuronide and sulfate conjugates serves as a long-lasting reservoir of estradiol that effectively extends its

terminal half-life Biological half-life (also known as elimination half-life, pharmacologic half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration ( Cmax) to half of Cmax in the bl ...

of oral estradiol. In demonstration of the importance of first-pass metabolism and the estrogen conjugate reservoir in the pharmacokinetics of estradiol, the terminal half-life of oral estradiol is 13 to 20 hours whereas with intravenous injection its terminal half-life is only about 1 to 2 hours.

References

External links

Metabocard of Estrone Glucuronide – Human Metabolome Database
{{Estrogen receptor modulators Estranes Estrogens Estrone esters Glucuronide esters Human metabolites

See also

References

External links