Prostaglandins and Related Prostanoid Compounds

In Scheme 1 the biosynthesis and the chemical structures of the classical prostaglandins (PGDj, PGEj, PGFj ) are summarized. It can be seen that these compounds differ from each other with respect to the chemical nature of the substituents at the prostane ring and in their stereochemistry. In Table 1 the scientific names of the biologically most relevant prostanoids and of other eicosanoids and related compounds are summarized. 

Finally a few remarks should be made about essential fatty acid (EFA) deficiency (section 5.2.2). Linoleic acid is the precursor of the eicosanoids, leukotrienes, prostaglandins, thromboxanes and related compounds (section 3.4). Until recently it was thought that the classic skin symptoms resulting from a deficiency were due to a lack of eicosanoids. However, the specific role of n-6 acids (such as linoleate) as opposed to n-3 acids (such as a-linolenate) in membrane fluidity and their function cannot explain their essentiality. For example, aspirin ingestion which effectively prevents prostanoid formation does not result in the appearance of EFA-deficiency symptoms. It is also generally accepted that at least some cell lines in culture do not have an EFA requirement - thus suggesting that EFAs are not essential for the formation and function of cellular membranes in general. 

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