The definitions used in this glossary of terminology either have been provided by the authors of the articles, or have been extracted wholly or in part, or paraphrased from the following sources: The American Medical Association Encyclopedia of Medicine, Charles B. Clayman, MD, Medical Editor, Random House, New York, 1989; Biotechnology from A to Z, 2d Edition, William Bains, Oxford University Press, New York, New York, 2002; A Dictionary of Genetics, 6th Edition, Robert C. King and William D. Stansfield, Oxford University Press, New York, New York, 2002; Dorland's Illustrated Medical Dictionary, 29th and 30th Editions, W. B. Saunders Company, Philadelphia, 2000, 2003; Genes VII, Benjamin Lewin, Oxford University Press, New York, New York, 2000; The Gale Encyclopedia of Genetic Disorders, Volumes I and II, Stacey L. Blachford, Ed., Thomson Learning, New York, New York, 2002; The Merriam-Webster Dictionary, Merriam-Webster, Inc., Springfield, Massachusetts, 1997; Molecular Biology of the Cell, 3rd Edition, Bruce Alberts, et al., Garland Publishing, 1994; The Random House Dictionary of the English Language, Unabridged Edition, 1966; Webster's Ninth New Collegiate Dictionary, 1991.
Any of a group of components derived from unsaturated 20-carbon fatty acids, primarily arachidonic acid, via the cyclooxygenase pathway; they are potent mediators of numerous different physiologic processes. The abbreviation for prostaglandin is PG; specific compounds are designated by adding a letter to indicate the type of ring structure and a numerical subscript to indicate the number of double bonds in the hydrocarbon skeleton (e.g., PGE2, etc.). Most naturally occurring prostaglandins have two double bonds and are synthesized from arachidonic acid. The 1 series and 3 series are produced by the same pathway starting with fatty acids that have one fewer or one more double bond than arachidonic acid. The subscript a or ß indicates the three-dimensional configuration of alcoholic groups attached to the ring structures (a denotes a substituent below the plane of the ring, ß, above the plane). The naturally occurring PGF's all have the a configuration. Prostaglandins act in the cells in which they are synthesized and surrounding cells, and their actions and effects vary with concentration, hormonal environment, and cell type.