The structure of Prostacyclin

Prostacyclin is a member of the family of lipid molecules known as eicosanoids. When given as a drug it is known as epoprostenol. (Dorlands)  It is produced in endothelial cells from prostaglandin H₂ (PGH₂) by the action of the enzyme prostacyclin synthase. Although prostacyclin is considered an independent mediator, it is called PGI₂ (prostaglandin I₂) in eicosanoid nomenclature, and is a member of the prostanoids (together with the prostaglandins and thromboxane). Figure 1: Structure of a Lipid. ... In chemistry, a molecule is an aggregate of at least two atoms in a definite arrangement held together by special forces. ... In biochemistry, eicosanoids are a class of oxygenated hydrophobic hormones that largely function as paracrine mediators. ... 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. ... Cells in culture, stained for keratin (red) and DNA (green). ... Chemical structure of prostaglandin E1 (PGE1). ... Ribbon diagram of the enzyme TIM. TIM is catalytically perfect, meaning its conversion rate is limited, or nearly limited to its substrate diffusion rate. ... 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. ... Chemical structure of prostaglandin E1 (PGE1). ... Thromboxane is a member of the family of lipids known as eicosanoids. ...

The series-3 prostaglandin PGH₃ also follows the prostacyclin synthase pathway, yeilding another prostacyclin, PGI₃.(Fischer, 1985)  The unqualified term 'prostacyclin' usually refers to PGI₂. PGI₂ is derived from the ω-6 arachidonic acid. PGI₃ is derived from the ω-3 EPA. Arachidonic acid is a polyunsaturated fatty acid with twenty carbons and four cis double bonds, the first at the omega-6 position (20:4n-6). ... Eicosapentaenoic acid (more commonly known as EPA; C20H30O2, all-cis-fatty acid 20:5 omega-3) is a polyunsaturated fatty acid that acts as a precursor for prostaglandin-3, which inhibits platelet aggregation) and thromboxane-3 groups. ...

Mode of action

Prostacyclin acts chiefly to prevent platelet formation and clumping involved in blood clotting. It is also an effective vasodilator. Prostacyclin's interactions in contrast to thromboxane, another eicosanoid, strongly suggest a mechanism of cardiovascular homeostasis between the two hormones in relation to vascular damage. A 250 ml bag of newly collected platelets. ... A thrombus is the final product of blood coagulation, through the aggregation of platelets and the activation of the humoral coagulation system. ... A vasodilator is a substance that causes blood vessels in the body to become wider by relaxing the smooth muscle in the vessel wall, or vasodilation. ... Thromboxane is a member of the family of lipids known as eicosanoids. ... Homeostasis is the property of an open system, especially living organisms, to regulate its internal environment to maintain a stable, constant condition, by means of multiple dynamic equilibrium adjustments, controlled by interrelated regulation mechanisms. ... Vascular is an adjective for the word vessel and refers to tube-like structures. ...

Pharmacology

Synthetic prostacyclin analogues (iloprost, cisaprost) are used intravenously, subcutaneously or by inhalation: iloprost, an inhalation solution, is sold under the name Ventavis® and is used to treat pulmonary arterial hypertension (PAH). ...

• as a vasodilator in severe Raynaud's phenomenon or ischemia of a limb;
• in pulmonary hypertension.

Its production is inhibited indirectly by NSAIDs, which inhibit the cyclooxygenase enzymes COX1 and COX2. These convert arachidonic acid to PGH₂, the immediate precursor of prostacyclin. A vasodilator is a substance that causes blood vessels in the body to become wider by relaxing the smooth muscle in the vessel wall, or vasodilation. ... In medicine, Raynauds phenomenon is discoloration of the fingers or toes due to emotion or cold in a characteristic pattern in time: white, blue and red. ... 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. ... Non-steroidal anti-inflammatory drugs, usually abbreviated to NSAIDs, are drugs with analgesic, antipyretic and anti-inflammatory effects - they reduce pain, fever and inflammation. ... Cyclooxygenase (COX) is an enzyme (EC 1. ...

References

• Dorlands Medical Dictionary. epoprostenol. URL accessed on February 10, 2006.

• Fischer S, Weber PC (Sep 1985). Thromboxane (TX)A3 and prostaglandin (PG)I3 are formed in man after dietary eicosapentaenoic acid: identification and quantification by capillary gas chromatography-electron impact mass spectrometry.. URL accessed on February 10, 2006. PubMed abstract

February 10 is the 41st day of the year in the Gregorian Calendar. ... 2006 (MMVI) is a common year starting on Sunday of the Gregorian calendar. ... February 10 is the 41st day of the year in the Gregorian Calendar. ... 2006 (MMVI) is a common year starting on Sunday of the Gregorian calendar. ...

See also

Essential fatty acid Essential fatty acids, or EFAs, are fatty acids that are required in the human diet. ...