Everything about Aromatase totally explained
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Aromatase is an
enzyme of the
cytochrome P450 superfamily, whose function is to aromatize
androgens (that is, to selectively increase their
aromaticity), producing
estrogens. As such, it's an important factor in
sexual development.
Genomics
In humans, the
gene CYP19, located on
chromosome 15q21.1, encodes the aromatase enzyme. CYP19 is present in an early-diverging
chordate, the
cephalochordate amphioxus (the Florida
lancelet,
Branchiostoma floridae), but not in the earlier diverging
tunicate Ciona intestinalis. Thus the aromatase gene evolved early in chordate evolution and doesn't appear to be present in non-chordate
invertebrates (for example
insects,
molluscs,
echinoderms,
sponges,
corals). However,
estrogens may be synthesized in some of these organisms, via unknown pathways.
Cellular and tissue location
The enzyme is located in the
endoplasmic reticulum of the cell and its activity is regulated by tissue specific
promoters that are in turn controlled by
hormones,
cytokines, and other factors. The principal action of the enzyme transforms
androstenedione to
estrone and
testosterone to
estradiol. The aromatase enzyme can be found in many tissues including
gonads,
brain,
adipose tissue,
placenta,
blood vessels,
skin,
bone,
endometrium as well as in tissue of
endometriosis,
uterine fibroids,
breast cancer, and
endometrial cancer.
Activity
Factors known to increase aromatase activity include
age,
obesity,
insulin,
gonadotropins, and
alcohol. Aromatase activity is decreased by
prolactin,
AMH, and
smoking.
Aromatase activity appears to be enhanced in certain estrogen-dependent local tissue next to breast cancer, endometrial cancer, endometriosis, and uterine fibroids.
Disorders
Aromatase excess syndrome
A number of investigators have reported on a rather rare syndrome of excess aromatase activity. In boys it can lead to
gynecomastia and in girls to
precocious puberty and
gigantomastia. In both sexes, early
epiphyseal closure leads to shortness.
Aromatase deficiency syndrome
This syndrome is due to a mutation of gene CYP19 and inherited in an
autosomal recessive way. Accumulations of androgens during pregnancy may lead to
virilization of a female at birth (males are not affected). Females will have primary
amenorrhea. Individuals of both sexes will be tall as lack of estrogen doesn't bring the epiphyseal lines to closure.
Aromatase inhibitors
The inhibition of the enzyme leads to profound
hypoestrogenism (low estrogen levels). Thus
aromatase inhibitors have become useful in the management of patients with
breast cancer whose lesion was found to be
estrogen receptor positive.
Further Information
Get more info on 'Aromatase'.
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