Metabolism of Estrogen

The word "estrogen" describes a collection of female hormones that are made by the ovaries in pre-menopausal women. According to a study published in the 2001 issue of "Applied Nutritional Science Reports," estradiol serves as the most potent form of estrogen. Other forms of estrogen include estrone and estriol. Estradiol converts readily to estrone and vice versa. After the menopausal period, the ovaries cease to be the prime producers of estrogens within the body. Endogenous estrogen production starts to rely on the tissue conversion of androstenedione, a hormone secreted by the adrenal glands, and body fat conversion.

Function

As mentioned by the study published in "Applied Nutritional Sciences Reports," estrogen may be considered the most important hormone in female reproduction. However, its use does not stop here. The hormone estrogen may serve other important functions. Estrogen plays an important role in the growth and development of many tissues within the body. It is also very important in bone formation and maintenance. Estrogen also gives some protection to the heart and its functions and it can also affect a person's behavior and mood. However, females are not the only ones dependent on estrogen function. It is now known that the prostate and testes, to some extent, also depend on this important hormone.

Estrogen Metabolism

The metabolism of estrogen is a very complex process that mainly occurs in the liver. The metabolism of estrogen may be divided into two phases: phase I, the hydroxylation phase that produces the larger bulk of endogenous estrogen, and phase II, the phase that ultimately leads to the excretion of estrogen metabolites through the feces and the urine. Phase I may be the most interesting phase for scientists because most of the development of breast cancer risks happens within this phase, according to the study published in "Applied Nutritional Sciences Reports." The glucuronidation step in phase II is another area of interest for many researchers. During this step, estrogen is packaged in preparation for its elimination through the feces. Some intestinal bacteria produce an enzyme, the beta-glucurodinase, that destroys this estrogen packaging, thereby further contributing to the risk for cancer development, particularly breast cancer. Factors that increase the activity of these harmful bacteria that produce beta-glucurodinase include a high-fat diet and a diet low in fiber.

Drug Interactions That Affect Estrogen Metabolism

Estrogen is primarily metabolized through the action of cytochrome P450 3A4, an enzyme produced by the liver, and to some extent the intestinal lining, for the metabolism of numerous drugs and toxins, according to Daily Med. Medications that induce or inhibit the action of cytochrome P450 3A4 affect the metabolism of estrogen. Inducers of cytochrome P450 3A4 include phenobarbital, carbamazepine and the anti-tuberculosis drug rifampicin. Inducers of cytochrome P450 3A4 reduce the concentration of estrogen in the body, thereby decreasing its potency. On the other hand, inhibitors of cytochrome P450 3A4 include antifungals such as itraconazole and ketoconazole, macrolide antibiotics such as clarithromycin and erythromycin, antiviral medication ritonavir and grapefruit juice. Cimetidine, an antacid, has also been implicated, in a study published in the April 2004 issue of the journal "Metabolism," as another inhibitor of estrogen metabolism. Inhibitors of estrogen metabolism increase the levels of estrogen in the body, potentially producing numerous side effects related to high estrogen levels.

Complications of High Estrogen Levels

Problems affecting estrogen metabolism can result in higher body levels of estrogen. Increased estrogen levels may affect the fertility of a female patient, resulting in decreased chances for pregnancy, according to a study published in the 2000 issue of the journal "Alcohol and Alcoholism." Another common outcome of high estrogen levels in the body is gynecomastia, the abnormal enlargement of breasts in men, according to the study published in "Metabolism." In the study published in "Applied Nutritional Science Reports," the researchers explained that chronic increases in estrogen levels in females may also be a risk for the development of breast cancer. Obesity and moderate alcohol consumption in women tend to increase endogenous estrogen in the body, predisposing a patient to cancer complications. A study published in the 2008 issue of the journal "Nature Clinical Practice Neurology" also mentioned that chronic exposure to high levels of endogenous estrogens may also increase the risk for the occurrence of stroke.