Adrenal steroidogenesis wiki

Catecholamines are produced in chromaffin cells in the medulla of the adrenal gland, from tyrosine , a non-essential amino acid derived from food or produced from phenylalanine in the liver. The enzyme tyrosine hydroxylase converts tyrosine to L-DOPA in the first step of catecholamine synthesis. L-DOPA is then converted to dopamine before it can be turned into noradrenaline. In the cytosol , noradrenaline is converted to epinephrine by the enzyme phenylethanolamine N-methyltransferase (PNMT) and stored in granules. Glucocorticoids produced in the adrenal cortex stimulate the synthesis of catecholamines by increasing the levels of tyrosine hydroxylase and PNMT. [4] [13]

Biosynthesis of steroid hormones requires a battery of oxidative enzymes located in both mitochondria and endoplasmic reticulum. The rate-limiting step in this process is the transport of free cholesterol from the cytoplasm into mitochondria. Within mitochondria, cholesterol is converted to pregnenolone by an enzyme in the inner membrane called CYP11A1. Pregnenolone itself is not a hormone, but is the immediate precursor for the synthesis of all of the steroid hormones. The following table delineates the enzymes required to synthesize the major classes of steroid hormones.

For women with idiopathic hirsutism, PCOS, or late-onset CAH, appropriate treatment decisions depend on each patient's desires and childbearing plans. Women who do not wish to become pregnant should use low-dose OCs. OCs containing less androgenic progestins, such as norgestimate, gestodene (not available in the United States), and desogestrel, seem to be the best choice, but some maintain that all preparations are comparable in efficacy. 24 These agents increase the level of SHBG and therefore decrease ovarian androgen production while decreasing the risk of endometrial hyperplasia often seen in anovulatory women. 25 , 26

Adrenal steroidogenesis wiki

adrenal steroidogenesis wiki


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