11Beta Hydroxysteroid dehydrogenase

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11β-Hydroxysteroid dehydrogenase (HSD11B) is the name of a family of enzymes that catalyze the conversion of inert 11 keto-products (cortisone) to active cortisol, or vice versa,^[1] thus regulating the access of glucocorticoids to the steroid receptors.

Contents 1 Function 2 Isoforms 3 See also 4 References 5 External links

[edit] Function

The mineralcorticoid receptor is stimulated by both aldosterone and cortisol, but there is a mechanism that protects the body from excess aldosterone receptor stimulation by glucocorticoids, which happen to be present at much higher concentrations than mineralcorticoids in the healthy individual. The mechanism consists of an enzyme called 11 β-hydroxysteroid dehydrogenase (11 β-HSD). This enzyme co-localizes with intracellular adrenal steroid receptors and converts cortisol (an active mineralcorticoid) into cortisone, a relatively inactive metabolite with little affinity for the mineralocorticoid receptors. Licorice, which contains glycyrrhetinic acid, can inhibit 11 β-HSD and lead to a mineralocorticoid excess syndrome.

[edit] Isoforms

In humans, there are two HSD11B isoforms:^[2]

HSD11B1	NADPH-dependent	Highly expressed in key metabolic tissues including liver, adipose tissue, and the central nervous system.	In these tissues, HSD11B1 reduces cortisone to the active hormone cortisol that activates glucocorticoid receptors.
HSD11B2	NAD+-dependent	Expressed in aldosterone-selective tissues.	In these tissues, HSD11B2 oxidizes cortisol to cortisone and prevents illicit activation of the mineralocorticoid receptor.

[edit] See also

• 11β-hydroxysteroid dehydrogenase type 1
• 11beta-hydroxysteroid dehydrogenase

[edit] References

[edit] External links

• MeSH 11-beta-Hydroxysteroid+Dehydrogenases

v • d • e Oxidoreductases: alcohol oxidoreductases (EC 1.1) 1.1.1: NAD/NADP acceptor Alcohol dehydrogenase · Aldo-keto reductase (1A1, 1B1, 1B10, 1C1, 1C3, 1C4, 7A2) · Aldose reductase · Carbohydrate dehydrogenases · Carnitine dehydrogenase · DXP reductoisomerase · Glucose-6-phosphate dehydrogenase · Glycerol-3-phosphate dehydrogenase · HMG-CoA reductase · 3-hydroxyacyl-CoA dehydrogenase · Beta-hydroxybutyryl-CoA dehydrogenase · Isocitrate dehydrogenase · IMP dehydrogenase · Β-Ketoacyl ACP reductase · Lactate dehydrogenase · Malate dehydrogenase · Phosphogluconate dehydrogenase · L-threonine dehydrogenase · L-xylulose reductase · Sorbitol dehydrogenase Hydroxysteroid dehydrogenase: 3 Beta (3-beta-HSD, NSDHL) · 11 Beta (HSD11B1, HSD11B2) · 17 Beta 1.1.2: cytochrome acceptor D-lactate dehydrogenase (cytochrome) · D-lactate dehydrogenase (cytochrome c-553) · Mannitol dehydrogenase (cytochrome) 1.1.3: oxygen acceptor Glucose oxidase · L-gulonolactone oxidase · Xanthine oxidase 1.1.4: disulfide as acceptor Vitamin K epoxide reductase · Vitamin-K-epoxide reductase (warfarin-insensitive) 1.1.5: quinone/similar acceptor Quinoprotein glucose dehydrogenase 1.1.99: other acceptors Choline dehydrogenase · L2HGDH

v • d • e Metabolism: lipid metabolism · ketones/cholesterol synthesis enzymes/steroid metabolism Mevalonate pathway To HMG-CoA Acetyl-Coenzyme A acetyltransferase · HMG-CoA synthase (regulated step) Ketogenesis HMG-CoA lyase · 3-hydroxybutyrate dehydrogenase · Thiophorase To Mevalonic acid HMG-CoA reductase To DMAPP Mevalonate kinase · Phosphomevalonate kinase · Pyrophosphomevalonate decarboxylase · Isopentenyl-diphosphate delta isomerase Geranyl- Dimethylallyltranstransferase · Geranyl pyrophosphate To cholesterol To lanosterol Farnesyl-diphosphate farnesyltransferase · Squalene monooxygenase · Lanosterol synthase 7-Dehydrocholesterol path Lanosterol 14α-demethylase · Sterol-C5-desaturase-like · 7-Dehydrocholesterol reductase Desmosterol path 24-dehydrocholesterol reductase To Bile acids Cholesterol 7α-hydroxylase · Sterol 27-hydroxylase Steroidogenesis To pregnenolone Side-chain cleavage To corticosteroids aldosterone: 18-hydroxylase cortisol/cortisone: 17α-hydroxylase · 11β dehydrogenase (HSD11B1, HSD11B2) both: 3β dehydrogenase · 21α-hydroxylase · 11β-hydroxylase To sex hormones To androgens 17α-hydroxylase/17,20 lyase · 3β dehydrogenase · 17β dehydrogenase · 5α reductase (1,2) To estrogens Aromatase Other/ungrouped Steroid metabolism: sulfatase (Steroid sulfatase) · sulfotransferase (SULT1A1, SULT2A1) Steroidogenic acute regulatory protein M: MET mt, a/u/y/n/h, r/g/c/p/i, f/s/l/o, m au/y/n/h, rgcp/i, f/s/l/o, m, epon meds(A16, C10),intm(a/u/y/n/h, r/g/c/p/i, f/s/o) M: END anat/phys/devp/horm/cell noco(d)/cong/tumr, sysi/epon proc, drug (A10/H1/H2/H3/H5)