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Encyclopedia > Prostaglandin

A prostaglandin is any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body. Every prostaglandin contains 20 carbon atoms, including a 5-carbon ring. They are mediators and have a variety of strong physiological effects; although they are technically hormones, they are rarely classified as such. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Alprostadil is a prostaglandin analogue used as a drug in the treatment of erectile dysfunction and has vasodilatory properties. ... Image File history File links Size of this preview: 486 × 600 pixelsFull resolution (891 × 1100 pixel, file size: 37 KB, MIME type: image/png) File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links Size of this preview: 486 × 600 pixelsFull resolution (891 × 1100 pixel, file size: 37 KB, MIME type: image/png) File historyClick on a date/time to view the file as it appeared at that time. ... Prostacyclin is a member of the family of lipid molecules known as eicosanoids. ... Some common lipids. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ... For other uses, see Animal (disambiguation). ... For other uses, see Carbon (disambiguation). ... This article or section does not cite any references or sources. ... Norepinephrine A hormone (from Greek όρμή - to set in motion) is a chemical messenger from one cell (or group of cells) to another. ...


The prostaglandins together with the thromboxanes and prostacyclins form the prostanoid class of fatty acid derivatives; the prostanoid class is a subclass of eicosanoids. Thromboxane is a member of the family of lipids known as eicosanoids. ... Prostacyclin is a member of the family of lipid molecules known as eicosanoids. ... Prostanoid is the term used to describe three classes of eicosanoids: the prostaglandins (mediators of inflammatory and anaphylactic reactions), the thromboxanes (mediators of vasoconstriction) and the prostacyclins (active in the resolution phase of inflamation. ... In biochemistry, eicosanoids are a class of oxygenated hydrophobic molecules that largely function as autocrine and paracrine mediators. ...

Contents

History and name

The name prostaglandin derives from the prostate gland. When prostaglandin was first isolated from seminal fluid in 1935 by the Swedish physiologist Ulf von Euler,[1] and independently by M.W. Goldblatt,[2] it was believed to be part of the prostatic secretions (in actuality prostaglandins are produced by the seminal vesicles); it was later shown that many other tissues secrete prostaglandins for various functions. Male Anatomy The prostate is a gland that is part of male mammalian sex organs. ... Male Anatomy The prostate is a gland that is part of male mammalian sex organs. ... 1935 (MCMXXXV) was a common year starting on Tuesday (link will display full calendar). ... This article or section does not cite any references or sources. ... Ulf von Euler, a Nobel laureat Ulf Svante von Euler (February 7, 1905 – March 9, 1983) was a Swedish physiologist and pharmacologist. ... Categories: Stub | Andrology | Exocrine system | Reproductive system ...


In 1971, it was determined that aspirin-like drugs could inhibit the synthesis of prostaglandins. The biochemists Sune K. Bergström, Bengt I. Samuelsson and John R. Vane jointly received the 1982 Nobel Prize in Physiology or Medicine for their researches on prostaglandins. Year 1971 (MCMLXXI) was a common year starting on Friday (link will display full calendar) of the 1971 Gregorian calendar. ... Aspirin, or acetylsalicylic acid (IPA: ), (acetosal) is a drug in the family of salicylates, often used as an analgesic (to relieve minor aches and pains), antipyretic (to reduce fever), and as an anti-inflammatory. ... Sune Karl Bergström (January 10, 1916 - August 15, 2004) was a Swedish biochemist. ... Bengt Ingemar Samuelsson (born May 21, 1934) is a biochemist. ... Sir John Robert Vane (March 29, 1927 - November 19, 2004) was a British pharmacologist. ... Year 1982 (MCMLXXXII) was a common year starting on Friday (link displays the 1982 Gregorian calendar). ... List of Nobel Prize laureates in Physiology or Medicine from 1901 to the present day. ...


Biochemistry

Biosynthesis

Biosynthesis of eicosanoids. (series-2)

Prostaglandins are found in virtually all tissues and organs. These are autocrine and paracrine lipid mediators that act upon platelet, endothelium, uterine and mast cells, among others. They are synthesized in the cell from the essential fatty acids[3] (EFAs). Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Autocrine signalling is a form of signalling in which the target cell is the secretory cell itself. ... Paracrine signalling is a form of signalling in which the target cell is close to the signal releasing cell, and the signal chemical is broken down too quickly to be carried to other parts of the body. ... A 250 ml bag of newly collected platelets. ... The endothelium is the layer of thin, flat cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. ... This article is about female reproductive anatomy. ... Mast cells A mast cell (or mastocyte) is a resident cell of areolar connective tissue (loose connective tissue) that contains many granules rich in histamine and heparin. ... Essential fatty acids, or EFAs, are fatty acids that cannot be constructed within an organism from other components (generally all references are to humans) by any known chemical pathways; and therefore must be obtained from the diet. ...

Name EFA Type Series
Gamma-linolenic acid (GLA) via DGLA ω-6 series-1
Arachidonic acid (AA) ω-6 series-2
Eicosapentaenoic acid (EPA) ω-3 series-3

An intermediate is created by phospholipase-A2, then passed into one of either the cyclooxygenase pathway or the lipoxygenase pathway to form either prostaglandin and thromboxane or leukotriene. The cyclooxygenase pathway produces thromboxane, prostacyclin and prostaglandin D, E and F. The lipoxygenase pathway is active in leukocytes and in macrophages and synthesizes leukotrienes. gamma-Linolenic acid (GLA) is an omega-6 essential fatty acid found primarily in vegetable oils. ... Dihomo-gamma-linolenic acid (DGLA) is 20-carbon ω-3 fatty acid. ... Omega-6 fatty acids are fatty acids where the term omega-6 signifies that the first double bond in the carbon backbone of the fatty acid, counting from the end opposite the acid group, occurs in the sixth carbon-carbon bond. ... Arachidonic acid (AA) is an omega-6 fatty acid 20:4(ω-6). ... Eicosapentaenoic acid (EPA or also icosapentaenoic acid) is an omega-3 fatty acid. ... It has been suggested that Fish oil, Oily fish be merged into this article or section. ... A phospholipase is an enzyme that converts phospholipids into fatty acids and other lipophilic substances. ... Cyclooxygenase (COX) is an enzyme (EC 1. ... Lipoxygenases are a class of enzymes which add oxygen to lipids. ... Leukotrienes are autocrine and paracrine eicosanoid lipid mediators derived from arachidonic acid by 5-lipoxygenase. ... Thromboxane is a member of the family of lipids known as eicosanoids. ... Prostacyclin is a member of the family of lipid molecules known as eicosanoids. ... White Blood Cells is also the name of a White Stripes album. ... A macrophage of a mouse stretching its arms to engulf two particles, possibly pathogens Macrophages (Greek: big eaters, makros = long, phagein = eat) are white blood cells, more specifically phagocytes, acting in the nonspecific defense as well as the specific defense system of vertebrate animals. ...


Release of prostaglandins from the cell

Prostaglandins were originally believed to leave the cells via passive diffusion because of their high lipophilicity. The discovery of the prostaglandin transporter (PGT, SLCO2A1), which mediates the cellular uptake of prostaglandin, demonstrated that diffusion can not explain the penetration of prostaglandin through the cellular membrane. The release of prostaglandin has now also been shown to be mediated by a specific transporter, namely the multidrug resistance protein 4 (MRP4, ABCC4), a member of the ATP-binding cassette transporter superfamily. Whether MRP4 is the only transporter releasing prostaglandins from the cells is still unclear. Prostaglandin transporter is a protein which carries prostaglandin across cell membranes. ... ABCC4 is a protein associated with prostaglandin transport. ... ATP-binding cassette transporters (ABC-transporter) are members of a a superfamily which is one of the largest, and most ancient families with representatives in all extant phyla from prokaryotes to humans. ...


Cyclooxygenases

Prostaglandins are produced following the sequential oxidation of AA, DGLA or EPA by cyclooxygenases (COX-1 and COX-2) and terminal prostaglandin synthases. The classic dogma is as follows: Cyclooxygenase (COX) is an enzyme (EC 1. ...

  • COX-1 is responsible for the baseline levels of prostaglandins.
  • COX-2 produces prostaglandins through stimulation.

However, while COX-1 and COX-2 are both located in the blood vessels, stomach and the kidneys, prostaglandin levels are increased by COX-2 in scenarios of inflammation. The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... In anatomy, the stomach is a bean-shaped hollow muscular organ of the gastrointestinal tract involved in the second phase of digestion, following mastication. ... Kidneys viewed from behind with spine removed The kidneys are bean-shaped excretory organs in vertebrates. ... An abscess on the skin, showing the redness and swelling characteristic of inflammation. ...


Prostaglandin E synthase

Prostaglandin E2 (PGE2) is generated from the action of prostaglandin E synthases on prostaglandin H2 (PGH2). Several prostaglandin E synthases have been identified. To date, microsomal prostaglandin E synthase-1 emerges as a key enzyme in the formation of PGE2. Prostaglandin E synthase (or PGE synthase) is an enzyme which generates prostaglandin E from prostaglandin H2. ...


Other terminal prostaglandin synthases

Terminal prostaglandin synthases have been identified that are responsible for the formation of other prostaglandins. For example, hematopoietic and lipocalin prostaglandin D synthases (hPGDS and lPGDS) are responsible for the formation of PGD2 from PGH2. Similarly, prostacyclin (PGI2) synthase (PGIS) converts PGH2 into PGI2. A thromboxane synthase (TxAS) has also been idenfitied. Prostaglandin F synthase (PGFS) catalyzes the formation of 9α,11β-PGF2α,β from PGD2 and PGF from PGH2 in the presence of NADPH. This enzyme has recently been crystallyzed in complex with PGD2[4] and bimatoprost[5] (a synthetic analogue of PGF). The lipocalin family of proteins is a functionally and structurally diverse group. ... Prostaglandin D2 synthase generates prostaglandin D2 from prostaglandin H2. ... Thromboxane-A synthase, also known as thromboxane synthetase, is an enzyme that catalyses the conversion of prostaglandin H2 to thromboxane A2. ...


Function

There are currently nine known prostaglandin receptors on various cell types. Prostaglandins ligate a subfamily of cell surface seven-transmembrane receptors, G-protein-coupled receptors. These receptors are termed DP1-2, EP1-4, FP, IP, and TP, corresponding to the receptor that ligates the corresponding prostaglandin (e.g., DP1-2 receptors bind to PGD2). There are currently nine known prostaglandin receptors on various cell types. ... The seven transmembrane α-helix structure of a G-protein-coupled receptor. ... Prostaglandin D2 is a prostaglandin which binds to the receptor PTGDR. Category: ...


These varied receptors mean that Prostaglandins thus act on a variety of cells, and have a wide variety of actions:

Prostaglandins are potent but have a short half-life before being inactivated and excreted. Therefore, they exert only a paracrine (locally active) or autocrine (acting on the same cell from which it is synthesized) function. Cultured Smooth muscle of the aorta. ... A 250 ml bag of newly collected platelets. ... Drawing by Santiago Ramón y Cajal of neurons in the pigeon cerebellum. ... Cultured Smooth muscle of the aorta. ... For other uses, see Calcium (disambiguation). ... Norepinephrine A hormone (from Greek όρμή - to set in motion) is a chemical messenger from one cell (or group of cells) to another. ... The term cell growth is used in two different ways in biology. ... Paracrine signalling is a form of signalling in which the target cell is close to the signal releasing cell, and the signal chemical is broken down too quickly to be carried to other parts of the body. ... Autocrine signalling is a form of signalling in which the target cell is the secretory cell itself. ...


Role in pharmacology

Inhibition

See Prostaglandin antagonist

A Prostaglandin antagonist is a hormone antagonist acting upon prostaglandin. ...

Clinical uses

Synthetic prostaglandins are used:

Parturition redirects here. ... Childbirth in a hospital. ... Spontaneous: Miscarriage Debate & social issues Breast cancer · Crime effect Crisis pregnancy centers Fetal pain · Religion · Mental health Pro-choice · Pro-life Selective abortion and infanticide Unsafe abortion · Violence History of abortion This box:      Mifepristone is a synthetic steroid compound used as a pharmaceutical. ... Patent ductus arteriosus (PDA) is a congenital heart defect wherein a childs ductus arteriosus fails to close after birth. ... A cyanotic heart defect is a congenital heart defect. ... A benign gastric ulcer (from the antrum) of a gastrectomy specimen. ... The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... Raynauds phenomenon (RAY-noz), in medicine, is a vasospastic disorder causing discoloration of the fingers, toes, and occasionally other extremities, named for French physician Maurice Raynaud (1834 - 1881). ... In medicine, ischemia (Greek ισχαιμία, isch- is restriction, hema or haema is blood) is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. ... In medicine, pulmonary hypertension (PH) is an increase in blood pressure in the pulmonary artery or lung vasculature, leading to shortness of breath, dizziness, fainting, and other symptoms, all of which are exacerbated by exertion. ... Erectile dysfunction (ED) or impotence is a sexual dysfunction characterized by the inability to develop or maintain an erection of the penis. ... Alprostadil is a prostaglandin analogue used as a drug in the treatment of erectile dysfunction and has vasodilatory properties. ...

References

  1. ^ Von Euler US. Über die spezifische blutdrucksenkende Substanz des menschlichen Prostata- und Samenblasensekrets. Klin Wochenschr 1935;14:1182–1183.
  2. ^ Goldblatt MW. Properties of human seminal plasma. J Physiol 1935;84:208-18. PMID 16994667.
  3. ^ Dorlands Medical Dictionary [1] URL reference on 10/23/05.
  4. ^ Komoto J, Yamada T, Watanabe K, Takusagawa F (2004). "Crystal structure of human prostaglandin F synthase (AKR1C3)". Biochemistry 43 (8): 2188-98. PMID 14979715. 
  5. ^ Komoto J, Yamada T, Watanabe K, Woodward D, Takusagawa F (2006). "Prostaglandin F2alpha formation from prostaglandin H2 by prostaglandin F synthase (PGFS): crystal structure of PGFS containing bimatoprost". Biochemistry 45 (7): 1987-96. PMID 16475787. 
  6. ^ Medscape Early Penile Rehabilitation Helps Reduce Later Intractable ED [2] URL reference on 10/23/05.

External links


  Results from FactBites:
 
Prostaglandin - Wikipedia, the free encyclopedia (969 words)
The prostaglandins together with the thromboxanes form the prostanoid class of fatty acid derivatives; the prostanoid class is a subclass of eicosanoids.
The cyclooxygenase pathway produces thromboxane, prostacyclin and prostaglandin D, E and F. The lipoxygenase pathway is active in leukocytes and in macrophages and synthesises leukotrienes.
Prostaglandins thus act on a variety of cells such as vascular smooth muscle cells causing constriction or dilation, on platelets causing aggregation or disaggregation and on spinal neurons causing pain.
  More results at FactBites »

 
 

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